Yemeni Security forces are searching for 23 suspected al-Qaeda members who broke out of a jail on Friday.
Some of them who escaped were convicted for the USS Cole attack
Thirteen of the men were convicted of carrying out bomb attacks on the destroyer USS Cole in 2000 and the French tanker Limburg in 2002.
The men broke out of a jail in the city of Sanaa and "are considered among the most important and dangerous members of al-Qaeda", an official told agency AFP.
He said they tunnelled 140 metres which took them to a nearby mosque.
The men then escaped as people left the mosque after Friday prayers.
The source said Fawaz al-Rabihi, who was convicted for the attack on the Limburg who had been sentenced to death, and Jamal al-Badawi, who received 10 years for the attack on the USS Cole were among those who escaped .
Al-Qaeda's Yemeni number two Abu Assem al-Ahdal may also be among those on the loose, the security source was quoted by AFP.
Yemen, which is the ancestral home of al-Qaeda leader Osama bin Laden, has been an ally of the US-led war on terror since the September 11 attacks in 2001.
Seventeen US sailors were killed when two suicide bombers blew themselves up on an inflatable raft moored next to USS Cole in the southern Yemeni port of Aden in October 2000.
In October 2002, the French tanker Limburg, was attacked off Yemen's south-eastern coast. An explosion killed one Bulgarian crew member and wounded 12 others.