Baghdad (AP): Nearly 1,000 people have been detained in a sweep to break al-Qaida in Iraq's sway in Iraq's third largest city, Mosul, but many of the fighters have fled to nearby areas, where troops are hunting for them, Iraqi officials said on Saturday.

Iraq's leaders presented the crackdown as a success so far in depriving the terror network of what has been its most prominent urban stronghold since it lost hold of cities in Iraq's western Anbar province.

But the flight of al-Qaida fighters raises the concern they can regroup elsewhere as has often happened in the past.

Yassin Majid, an adviser to Prime Minister Nouri al-Maliki adviser, said most of the leading insurgents had fled to the outskirts of Mosul or to a neighbouring country amid the operations. He did not name the neighbouring country. Mosul is about 100 km from the Syrian and Turkish borders.

"Operations will continue and the Iraqi army will not leave Mosul until security and stability have been accomplished," he told AP in a telephone interview.

Duraid Kashmola, the governor of Ninevah province, where Mosul is the capital, said this week's sweep would "not ease for fear gunmen might return back in strength to the field."

The sweep was launched Thursday, after five days of preparatory operations and arrests in the city. US-backed Iraqi police and soldiers have been conducting raids on homes and have fanned out with checkpoints on city streets, though no clashes have been reported in the city, 360 kmnorthwest of Baghdad.

Interior Minister Jawad al-Bolani said 1,068 people have been detained over the past week, but 94 were cleared and have since been released. Kashmola said most of those arrested were al-Qaida members.