According to international law, Iran cannot unilaterally decide to close the waterway because part of it is in Oman’s territorial waters.
However, Iran claims to have total control of the waterway, CNN reports.
On Wednesday, Iran's Navy Commander Rear Admiral Habibollah Sayyari said, "Iran has total control over the strategic water way," adding that, "Closing the Strait of Hormuz is very easy for Iranian naval forces." The vice president, Mohammad Reza Rahimi, issued his threat on Tuesday.
Would Oman, a US ally, step in to stop Iran? The sultanate enjoys good standing not only with the US, but with the whole region, including Iran. With the Fifth Fleet around the corner, Oman has not needed to take the lead in responding to Iranian provocations.