Hundreds of Taliban fighters launched raids on police posts near the strategic town of Chora in Uruzgan province Saturday, forcing Nato, backed by fighter jets, to respond. Fighting was continuing Tuesday, and some officials reported there have been dozens of civilian casualties.

Also late Monday, Taliban occupied Miya Nishin district in neighbouring Kandahar province, said provincial police chief Esmatullah Alizai. Authorities were planning an operation to retake the remote area, he said.

The insurgent push in the south appears to be the biggest Taliban offensive of the year and marks a change in tactics.

Until now, militants have relied largely on suicide and roadside bombings this year as Nato forces have escalated their operations to root them out. Violence has swelled, claiming about 2,400 lives during 2007, according to an Associated Press tally of figures from Western military and Afghan officials.

Maj Gen Jouke Eikelboom, director of operations with the Dutch military, said Monday that Karzai and the Uruzgan governor sought military support after the attack on the police posts.

"It has been a contested area for some number of months," said Maj. John Thomas, a Nato spokesman. "(The Taliban) are making an effort right now to establish control in that area," he said, predicting more fighting in coming days.

Thomas said he could not pin down the number of fighters that Nato troops were up against but that the battle was not over. "There's reason to believe that the situation on the ground is still unstable," he said.

Precise casualty figures were not available because of the continued fighting, though two Afghan officials said more than 100 people have been killed, including at least 16 police. A Dutch soldier also died, and three others were wounded.

A summary of fighter jet activity from Sunday sent out by the US Central Command hinted at the ferocity of the battles, detailing at least eight aircraft dropping bombs or firing on the area.

Afghan officials said Taliban fighters sought shelter in civilian homes and that Nato bombers targeted them.

Nearby in Kandahar, Taliban occupied the district of Miya Nishin late Monday, said provincial police chief Esmatullah Alizai. Authorities were planning an operation to retake the remote area, he said.

Thomas said that Nato-led troops stand ready to help Afghan government actions in the area.

Reports of civilian deaths in from the fighting in Uruzgan were coming from various quarters.

One wounded man, Janu Akha, at the main Uruzgan hospital told The Associated Press that 18 members of his family had been killed.

Mullah Ahmidullah Khan, the head of Uruzgan's provincial council, estimated the clashes in Chora killed 60 civilians, 70 suspected Taliban militants and 16 Afghan police.

"I have talked to President Karzai and asked him to send helicopters to ferry the wounded to Kabul," he said.

An official close to the governor who asked not to be identified when talking about preliminary estimates, said 70 to 75 civilians were killed or wounded, while more than 100 Taliban and more than 35 police were killed.