Qaeda militants tunneled their way out of a Yemeni prison in the lawless south Wednesday, deepening the chaos of a nation where protesters are trying to topple the regime. The escape from the Mukalla prison in Hadramout province is the latest sign that militants are seizing on the mayhem to operate more freely, something the US fears will become an increasing international threat if the impoverished nation grows even more unstable. Hundreds of militants have also taken control of two southern towns in recent weeks. The jailbreak in the early hours of Wednesday harked back to one in February 2006, when 23 Al-Qaeda militants broke out of a detention facility in Sana'a, Yemen's capital. They included Nasser Al'-Wahishi, who went on to become the leader of the Yemen-based Al-Qaeda in the Arabian Peninsula, which Washington says is already the terror network's most active branch. Yemeni security officials said the escapees on Wednesday included two Syrians, two Saudis and 16 members of an Al-Qaeda cell blamed for at least 13 terror attacks. A growing Al-Qaeda threat would deepen the country's predicament. Already, much of Yemen has been paralyzed by months of massive protests demanding the ouster of longtime leader Ali Abdullah Saleh. The crisis shifted to armed street conflict between troops loyal to Saleh and rival tribal fighters. The president of nearly 33 years was badly wounded in an attack on his Sana'a compound earlier this month, and his departure for medical treatment in neighboring Saudi Arabia has failed to break the deadlock. The unrest also has significantly worsened conditions for most Yemenis, whose lives had been difficult even before the start of the unrest in February. Most now suffer from an acute shortage of drinking water, lengthy power cuts and soaring food prices. The United States already has warned that militants in Yemen were taking advantage of the unrest to operate more openly and have been able to acquire and hold more territory. US State Department spokesman Mark Toner said Wednesday that Washington was trying to learn all the facts about the jailbreak and emphasized that cooperation with Yemeni officials on counterterrorism was continuing despite the turmoil. “Obviously the instability in Yemen is the kind that Al-Qaeda feeds on or tries to take advantage, exploit, throughout the world. It's concerning, but our cooperation continues,” he told reporters in Washington. A total of 57 Al-Qaeda-linked militants, including several on death row, attacked their guards and seized their weapons before they made their way through a 45-yard tunnel to freedom. Simultaneously, bands of gunmen opened fire at the prison from outside to divert the guards' attention, the Yemeni security officials said.