Yemen's pro-government forces have retaken most of the strategic province of Lahej, once the main southern enclave of Shiite rebels who control the country's capital and much of the north, officials and witnesses said Wednesday. Pro-government forces have made a series of gains in recent weeks in southern Yemen with the help of a Saudi-led and U.S.-backed coalition that has been waging an air campaign against the Iran-allied rebels and allied military units since March. The officials say the Houthi rebels appear to have lost most of their heavy weapons in a battle Monday to defend the key military base of al-Anad in Lahej. There were no immediate reports on casualties from the fighting in the strategic province. Witnesses say the remaining rebels in Lahej have taken refuge in surrounding farmland. In Taiz, Yemen's third largest city, five civilians were killed in clashes between rebels and pro-government troops at a state security building that the Houthis have been using as a base since March, medical officials said. Pro-government forces have cordoned off the southern port city of Aden and set up security checkpoints. Those residing outside Aden are not allowed to enter the city for fear they may be "Houthi sleeper cells," a security official said. Meanwhile, residents in Sanaa are stocking up on rare food and fuel supplies after the government 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 Tuesday that commercial flights would be diverted from the capital to the southern port of 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." Residents in the capital scrambled to stock up on food from stores as the black-market price for 20 liters of petrol jumped to $60 in recent days compared to an official price of $15. 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.