The Revolutionary Guard is repeating its warnings to shipping companies that it is dangerous to attempt what Iran calls illegal shipping routes between the Persian Gulf and the world's oceans.
According to the Revolutionary Guard, Iran has attacked four ships transferring oil between tankers in the northern Persian Gulf. The Guard says three other ships have hit mines in the Strait of Hormuz.
Fossil fuel transport in the area has been severely hampered since the US and Israel began their war against Iran last winter. The war is relatively calm at the moment, but there are reports that the US is planning new offensives.