Tehran: Yemen's Houthis on Friday took control of Mayyun Island in the Red Sea, tightening their grip over the strategic Bab al-Mandeb shipping lane, a local government official and eyewitnesses told AFP.

The island, also known as Perim, sits in the middle of the strait and divides the waterway into two lanes.

"Boats carrying armed Houthi fighters reached Mayyun Island after government forces withdrew from it yesterday," the local government official said.

"The Houthis have completed their takeover of the Bab al-Mandab area and Mayyun Island, which is located in the middle of the strait," he added, speaking to AFP on condition of anonymity.

An eyewitness said gunmen were "deploying along the Bab al-Mandab shore and are driving around in military vehicles".

The latest advance comes after hundreds of people were killed in fighting that began last week when the Iran-backed Houthis launched an offensive against Riyadh-backed Yemeni government forces around Bab al-Mandab.

The waterway has assumed greater strategic importance since the outbreak of the wider Middle East war, during which Iran blockaded the Strait of Hormuz.

The local government official said the number of Houthi fighters on Mayyun Island was "not large", adding that they were likely to position themselves on hills overlooking the Bab al-Mandab.

The waterway, a key route for Saudi oil exports, includes four strategically important islands, Zuqar, which the Houthis seized on Thursday, Mayyun and the two Hanish islands.

Government military sources told AFP that Houthi forces had also surrounded government troops on the Hanish islands.

The sources said they did not know the current status of the troops, whose strength is estimated at more than 2,000, but believed the Houthis had ordered them to surrender.

A senior military official said the besieged forces had appealed to authorities for "rescue, food and water, and the lifting of the siege, which would require air support".