Residents in the Yemeni capital Sanaa are stocking up on rare food and fuel supplies after the government in exile decided to divert aid ships from the Houthi rebel-held north to loyalist areas farther south.

Sources in Yemen's government confirmed the move, though there has been no official announcement, and Yemen's exiled information minister said on Tuesday that commercial flights would be diverted from the capital to the southern port of Aden.

The decisions come as southern fighters backed by weapons and air strikes by neighbouring Gulf states have made rapid gains on southern battlefields against the Iran-allied Houthis.

A Saudi-led alliance has been bombing Yemen's dominant group since March in support of the country's exiled leadership, which now seeks to reestablish its base from Aden.

"Gas stations have closed, and there are fears that the coalition will impose a siege on Sanaa and the cities of the north. We're afraid," said Ali Saleh, who was searching for ways to fill up his taxi.

"Everybody's afraid of the possibility that fighting will break out in Sanaa, and we ask God to protect us," he said.

Residents in the capital scrambled to stock up on food from stores as the black market price for 20 litres of petrol jumped to 60 dollars in recent days compared to an official price of 15 dollars.

The Arab coalition has enforced a near-blockade on the country to prevent arms shipments, but had for almost four months allowed trade and aid vessels to dock at Houthi-controlled ports to relieve hungry and impoverished Yemenis in the north.

The Houthi movement, hailing from a Shi'ite sect in Yemen's far north, seized Sanaa and much of the rest of the country in September in what they have called a revolution.

Southern forces loyal to the exiled government have been on the defensive in four months of fighting and bombing that have killed over 4,000 people, but have made lightning advances northward, seizing Yemen's biggest military base this week.

Ali al-Ahmadi, a spokesman for the anti-Houthi forces, told Reuters the Houthis were ejected from all of the key province of Lahej on Wednesday, bringing the number of southern provinces under anti-Houthi control to three.

The militia sources said 13 internally displaced people returning to their homes in the area were killed by landmines planted by the Houthis amid the fighting.

Early on Thursday, the Saudi-led coalition said a ground forces soldier by the name of Yahya Miteb Shamri died after he was hit by a projectile in Saudi Arabia's Jizan province, which shares a border with Yemen. The nationality of the soldier was not identified. – Reuters