AL MUKALLA, Yemen — Militants from Al Qaeda’s Yemeni affiliate stormed this southern port city early on Thursday, attacking several government buildings including the central prison, where they freed hundreds of inmates, according to residents.
It appeared to be the first large-scale operation by the affiliate, , since the beginning of a led by Saudi Arabia on more than a week ago, and a further expansion of the violence rapidly spreading across the country.
In an apparently coordinated offensive that began after midnight, the militants attacked security headquarters, the presidential palace and other official installations. That appeared to be intended as a diversion before the militants attacked the central security prison, their primary target.
Witnesses near the prison said they saw hundreds of inmates file out. Afterward, looters descended on the prison, they said.
Al Mukalla, the capital of the oil-rich Hadhramaut Province, had been spared much of the recent unrest in Yemen’s accelerating war. The fighting began in earnest weeks ago in the southern port city of Aden, where forces loyal to the president of Yemen, Abdu Rabbu Mansour Hadi, who is now exiled, clashed with allies of , a northern militia that controls the capital and forced Mr. Hadi from power.
Last week, Saudi Arabia and a coalition of countries, with support from the United States, began a broad military offensive against the Houthis, ostensibly aimed at restoring Mr. Hadi to power. Many have begun to question the aims of the military campaign, as the Houthis have continued to advance, including deeper into Aden, and the toll of the fighting on Yemeni civilians has become increasingly severe.
The attack on Thursday was the first indication of how Al Qaeda was capitalizing on the growing anarchy, at a time when Yemen’s American-trained counterterrorism troops have come under attack by the Saudi-led military coalition.
A similar attack by Al Qaeda in late March on a town in Lahj Province forced the Obama administration to withdraw its last military advisers to Yemen, who were stationed at a base near the town. The administration has said it is providing intelligence, logistical support and targeting guidance to the Saudi-led campaign.
Explosions and gunfire could be heard throughout Al Mukalla overnight. Clashes continued in the city later on Thursday morning, as local military units backed by helicopters fought gun battles with militants in Al Mukalla’s old city, according to witnesses.