Six ships turned around on the first day of the Strait of Hormuz blockade, according to the U.S. military.

No ships have succeeded in passing through a U.S. naval blockade targeting Iran’s ports and coastal areas, while six merchant vessels complied with orders to turn back, the U.S. military said on Tuesday, The Caspian Post reports, citing foreign media.

The development comes on the first day of the blockade ordered by U.S. President Donald Trump after peace talks between the US and Iran collapsed.

The U.S. military stated that the blockade, which began on Monday, applies only to vessels traveling to or from Iran, including those heading to or departing from all Iranian ports in the Gulf and the Gulf of Oman.

“During the first 24 hours, no ships made it past the U.S. blockade and six merchant vessels complied with direction from U.S. forces to turn around to re-enter an Iranian port on the Gulf of Oman,” the U.S. military’s Central Command said in its statement.