The Navy of Iran's Islamic Revolutionary Guard Corps (IRGC) stopped four vessels seeking to cross the Strait of Hormuz through the southern route within the past 24 hours, state-run IRIB TV reported Saturday.
The report described the southern route as "illegal and unsafe," saying the vessels changed course after warning shots were fired.
It added that vessels using the southern route in recent days have experienced incidents and lost assets.
Iran tightened its grip on the strait on February 28, barring safe passage of vessels belonging to or affiliated with Israel and the United States following their joint strikes on Iranian territory.
In recent days, the US military has launched multiple waves of strikes against Iranian targets, saying they were in response to Iranian attacks on vessels in the strait and aimed at "degrading Iran's ability to threaten commercial shipping."
Iran has responded with missile and drone attacks targeting US military bases and facilities in the region.
