According to the source, Iran has not officially confirmed the order, but Tehran has for many years threatened to block the narrow, strategically important Strait of Hormuz - the world's most important transport route for oil exports from the Gulf countries.
At the same time, the US Department of Transportation is urging commercial ships to stay away from the area after the US and Israel launched heavy bombing attacks on Iran.
The Strait of Hormuz, the Persian Gulf, the Gulf of Oman and the Arabian Sea are subject to "significant military activity," and "it is recommended that vessels stay away from this area if possible," according to the department's maritime authority.
