ADEN - Al Qaeda-linked militants have released a Saudi Arabian diplomat kidnapped in southern Yemen in March, a tribal source said on Sunday, after mediation by local tribal leaders.

Abdallah al-Khalidi, the deputy consul in the Saudi consulate in the Yemeni port city of Aden, was kidnapped by Islamist militants demanding a ransom and the release of women prisoners held in the kingdom.

"Tribal mediators received the Saudi diplomat (late on Saturday) and he will be moved to Sanaa in the next few hours," Sheikh Tareq al-Fadli, a tribal chief, told Reuters.

The terms of Khalidi's release were not clear.

A militant who claimed responsibility for the kidnapping in May had threatened to kill Khalidi unless a ransom was paid and al Qaeda prisoners were freed from Saudi jails.

Last month, five al Qaeda-linked women detainees were freed by Saudi authorities. Interior Ministry spokesman Mansour al-Turkis stressed at the time that the move was not linked to demands by the al Qaeda captors of the Saudi diplomat in Yemen.

Kidnapping is common in Yemen, frequently in the context of regional or tribal disputes with Yemeni authorities. The victims are sometimes held for ransom, particularly if they are foreigners.

Yemen has been in turmoil since popular protests broke out last year and led to the ousting of former President Ali Abdullah Saleh.

Khalidi had appeared in two videos posted on the Internet after his abduction begging King Abdullah to meet his captors' demand for the release of women detainees.

The United States and its Gulf Arab allies have watched with mounting alarm as Islamist fighters, emboldened by the political instability in Yemen, gained ground in the south of the country in the past year.

Al Qaeda in the Arabian Peninsula, the al Qaeda group operating in Yemen, is seen by US officials as the most dangerous offshoot of the global militant network.