An official security source said the ministry of defense ordered an immediate investigation into the incident to discover who helped the prisoners escape from the high-security jail supervised by the Yemeni intelligence service.
The prison-break coincided with the trial of Mohammed al-Ahdal, who is expected to appear later Saturday in a special court dealing with terrorism cases on charges of financing terrorist activities.
The escape of al-Qaida suspects also came two weeks after two followers of religious rebel leader Badreddine al-Houthy managed to escape from prison, prompting the Yemeni authorities to reshuffle the prison's officials, including the dismissal of the prison chief and his deputy.
The Yemeni authorities announced last week they arrested 19 people who fought in Iraq and are believed to belong to al-Qaida group in that country, led by Jordanian-born Abu Musab Zarqawi.
An official source said the cell was planning to carry out terrorist operations in the city of Aden in south Yemen, targeting U.S. citizens and a hotel largely frequented by American expatriates.
The source said the cell returned from Iraq with clear instructions from Zarqawi to assassinate U.S. nationals in Yemen.