Trump’s threat to blockade Hormuz: Why it’s war’s latest major escalation

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In a social media post on Sunday, Trump said the US Navy “will begin the process of BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz”. This article will be opened in a new browser windowlist 3 of 3Starmer says UK will not support US blockade of Strait of Hormuzend of listTrump’s comments have raised concerns about the status of the two-week ceasefire between the US and Iran announced last week. Chris Featherstone, a political scientist at the University of York, told Al Jazeera that Trump’s threat to blockade the Strait of Hormuz is “absolutely an escalation” in the US and Israel’s war on Iran. “Trump is using the threat of the blockade as a tool in the negotiations with Iran. Trump has said Iran holds no cards, and this attempt to leverage a blockade on Iran would constitute an attempt to further pressure Iran to comply with US goals in the negotiations,” he said. What could the blockade look like? Here’s what we know: Shortly after the US and Israel began strikes on Iran on February 28, Iran essentially took control of the Strait of Hormuz, a vital chokepoint for the global energy market. Before the war began, 20 percent of the world’s oil and liquefied natural gas (LNG) supplies were shipped through the strait. After the Pakistan-brokered ceasefire came into force on Wednesday, Tehran confirmed it would allow shipping through the Strait of Hormuz for the duration of the two-week agreement, easing a disruption that had sent global oil and gas prices soaring. However, it has been unclear whether Iran has been collecting fees for passage during the ceasefire. During the war, only a few ships from specific countries considered friendly to Iran and those that paid tolls were granted safe passage. After weekend talks in Pakistan ended without a deal, Trump threatened to blockade the Strait of Hormuz and also accused Iran of “extortion”. He added that the US Navy would hunt down and interdict ships in international waters that had paid Iran a toll to traverse the strait. Later, the US military said it would block all maritime traffic entering and exiting Iranian ports, including those in the Gulf and the Gulf of Oman. The blockade is to begin at 10am Washington, DC, time (14:00 GMT) on Monday. The US ‌military’s Central Command (CENTCOM), which has responsibility for operations in the Middle East, told the Reuters news agency that the US ⁠military ⁠will enforce a blockade in the Gulf of Oman and ⁠the Arabian Sea east of the Strait of ⁠Hormuz and it will apply to all vessels regardless of flag. “Any vessel entering or departing the blockaded ⁠area without authorisation is subject to ⁠interception, diversion and capture,” it said. “The blockade will not impede neutral transit passage ‌through the Strait of Hormuz to or from non-Iranian ‌destinations.” Iran’s armed forces, however, said the US “imposition of restrictions on the movement of vessels in international waters is an illegal act and amounts to piracy”. Jason Chuah, professor of maritime law at City St George’s, University of London, and the Maritime Institute of Malaysia, told Al Jazeera that Washington’s actions wouldn’t be a classic blockade but a case of “sanctions with warships doing the bidding of President Trump”. “It would be much more like a steady pattern of stopping, boarding and seizing vessels thought to be linked to Iran, essentially sanctions enforcement at sea,” he said. Chuah said the legality of such a blockade by the US is “tricky”. “The United States is not a party to the United Nations Convention on the Law of the Sea, but that does not mean it is free to blockade as it sees fit,” he said. “The basic rules about freedom of navigation and passage through key waterways are widely accepted as customary international law, so they bind states whether they’ve signed the treaty or not.” He added: “Now, if you want to call something a blockade in legal terms, you’re really in the territory of the law of armed conflict at sea – think the San Remo Manual on International Law Applicable to Armed Conflicts at Sea. That, however, assumes you’re in an actual armed conflict, that you’ve declared the blockade, that it’s effective and that it’s applied even-handedly to neutral ships. That framework sets a high lawfulness bar for blockades.” Chuah said that even if Trump uses sanctions as a justification for Washington’s actions regarding Iranian ports, it does not fully resolve the legal issues. “Even quite robust domestic sanctions don’t automatically give you the right under international law to stop foreign ships on the high seas without consent or backing from the United Nations Security Council. At best, sanctions may justify why you act but not always where you can act,” he said. So far, only the United Kingdom has clearly stated that it will not join Trump’s blockade of Iranian ports. In an interview with BBC 5 Live on Monday, British Prime Minister Keir Starmer said he is focusing on reopening the Strait of Hormuz “as quickly as possible” to reduce global energy prices. “We’re not supporting the blockade, and all of the marshalling diplomatically, politically and capability, … that’s all focused, from our point of view, on getting the strait fully open,” he said. Meanwhile, China has urged calm on all sides. Keeping the critical waterway safe, stable and unimpeded serves the common interests of the international community, Ministry of Foreign Affairs spokesperson Guo Jiakun said, adding that China stands ready to work with all sides to safeguard energy security and supplies. Featherstone noted that one of the standout features of the US-Israel war on Iran has been how many US allies, such as the UK, have been unwilling to get involved. “Given this blockade would be occurring in the midst of the negotiations over a ceasefire, risking the talks falling apart, it’s unlikely any allies would want to get involved now,” he said. “As with other elements of this war, the [US] administration hasn’t outlined the purpose of this potential blockade. US allies will likely want to know the purpose of the blockade before they commit and risk reprisals,” he added. Even though Iran has become accustomed to US sanctions and has continued to function during the war, a blockade like this could inflict more damage on Iran’s economy. The unified command of the Iranian armed forces has said ports in the Gulf and the Sea of Oman are “either for everyone or for no one”, state broadcaster IRIB reported. “The Armed Forces of the Islamic Republic of Iran consider defending the legal rights of our country a natural and legal duty and, accordingly, exercising the sovereignty of the Islamic Republic of Iran in the territorial waters of our country is the natural right of the Iranian nation,” IRIB quoted Iran’s military as stating. “Enemy-affiliated vessels” will not have the right to pass through the Strait of Hormuz while other vessels will be allowed passage, subject to regulations by Tehran, the statement said. “The criminal US’s imposition of restrictions on the movement of vessels in international waters is an illegal act and amounts to piracy.” If the security of the ports is threatened, no port in the region “will be safe”, the statement said. Reporting from Doha, Qatar, Al Jazeera’s diplomatic editor James Bays said Washington’s blockade may seek to hit the Iranian economy, which has been doing well despite the war by continuing to get its oil supply through the Strait of Hormuz. “It’s almost a race to the damage on Iran’s economy, a country that’s had sanctions since 1979, that’s very economically resilient although it has deep economic problems,” he said. Featherstone said Iran is relatively used to the US having a stranglehold on its economy. “Iran has experienced enormous US sanctions for decades, and for most of that time, the US sanctions regimes have prevented any nation that trades with the US from trading with Iran,” he said. “However, after the extent of the US and Israeli strikes on Iran, this would impact their ability to rebuild,” he added. On Wednesday, the Islamic Revolutionary Guard Corps (IRGC) released a map of the Strait of Hormuz showing a safe route for ships to follow through the strait, avoiding mines it has laid. The map appears to direct ships farther north towards the Iranian coast and away from the traditional route closer to the coast of Oman. In a statement, the IRGC said all vessels must use the new map for navigation due to “the likelihood of the presence of various types of anti-ship mines in the main traffic zone”. In his Truth Social post on Sunday about the blockade of the Strait of Hormuz, Trump said US forces will begin clearing the mines that Iran has placed in the strait and added that NATO countries like the UK would help in the process. But on Monday, Starmer told BBC 5 Live that while the UK has “minesweeping” capacities, it would not get involved in “operational matters”. Meanwhile, Japan said it has yet to decide whether to deploy its Self-Defence Forces for minesweeping operations in the Strait of Hormuz. Chief Cabinet Secretary Minoru Kihara told reporters that Japan is urging progress towards a comprehensive understanding between the US and Iran. “What is most important is that de-escalation, including securing the safety of navigation through the Strait of Hormuz, is actually achieved,” Kihara said, according to the Kyodo News agency. During the US-Israel war on Iran, Tehran has allowed a small number of ships from certain countries it considers “friendly nations”, such as India, China, Japan, Turkiye and Pakistan, to pass through the strait. Some vessels that also paid a toll to Iran were allowed to pass. At least two tolls for ships are believed to have been paid in Chinese yuan in what appears to be a strategy to weaken the US dollar and avoid US sanctions. China, which buys 80 percent of Iran’s oil, already pays Tehran in yuan. On Friday, Iran said it was considering a proposal to charge future tolls in its own currency, the rial. Chuah told Al Jazeera that the effects of Washington’s blockade of Iranian ports would spill over quickly to Indian, Chinese, Japanese, Turkish and other countries’ shipping. “You don’t have to be Iranian to get caught up in it [the blockade]. If there’s any Iranian link in the cargo, financing or ownership chain, you’re suddenly in the risk zone,” he said. He warned that insurance premiums will likely rise, making global banks nervous. He said the global tanker market will also start to fragment into separate risk tiers. “The moment interdictions begin, neutral shipping starts to feel a lot less neutral,” he said. He added that the bigger picture of such a blockade is also worrying. “If major powers start routinely stopping ships based on who they’re linked to rather than where they are or what they’re doing, that chips away at the stability of the whole system. The real issue isn’t just Iran – it’s what this does to the rules everyone else relies on,” he said. Advertisement AboutAboutShow moreAbout UsCode of EthicsTerms and ConditionsEU/EEA Regulatory NoticePrivacy PolicyCookie PolicyCookie PreferencesAccessibility StatementSitemapWork for usConnectConnectShow moreContact UsUser Accounts HelpAdvertise with usStay ConnectedNewslettersChannel FinderTV SchedulePodcastsSubmit a TipPaid Partner ContentOur ChannelsOur ChannelsShow moreAl Jazeera ArabicAl Jazeera EnglishAl Jazeera Investigative UnitAl Jazeera MubasherAl Jazeera DocumentaryAl Jazeera BalkansAJ+Our NetworkOur NetworkShow moreAl Jazeera Centre for StudiesAl Jazeera Media InstituteLearn ArabicAl Jazeera Centre for Public Liberties & Human RightsAl Jazeera ForumAl Jazeera Hotel PartnersFollow Al Jazeera English: