Yemen released 170 men it had arrested on suspicion of having ties to Al Qaeda, security officials said Sunday, two weeks after the terror group announced that Yemen had become the base of its activities for the whole Arabian peninsula.

The announcement also comes as government forces say they are poised to sweep through the northern city of Marib to combat an entrenched Al Qaeda presence that includes both Yemenis and Saudis.

The officials who announced the release spoke on condition of anonymity because they are not allowed to speak to the press.

The men were freed Friday and Saturday after signing pledges not to engage in terrorism — a strategy the Yemeni government has often used with those suspected of fighting in militant causes abroad. Local tribal leaders are also expected to guarantee the good behavior of the released.

The practice stems in part from the powerful role played by the tribes across the rugged Yemeni countryside as well as the comparative weakness of the central government.

In the past, such releases have raised concern in the United States and increased its reluctance to release Yemeni detainees from the Guantanamo Bay detention facility.

Yemen has said it expects most of the 100 remaining Yemenis at Guantanamo to be sent home after President Barack Obama ordered the prison shut within a year.

Elements of al-Qaida have long found a haven in Yemen's remote hinterland. Last month, Saudi Al Qaeda fugitives in Yemen and their Yemeni associates announced in an Internet video that they were joining forces to form a single group.

On Saturday, Saudi Arabia issued a list of 85 most wanted living abroad that included two Yemenis. Many of the Saudis on the list are suspected of hiding out in Yemen as well.