The insurgents meanwhile warned civilians to stay away from foreign forces, saying they were planning their own new campaign of ambushes, suicide attacks and roadside bombings.

A defence ministry spokesman told reporters in Kabul the operations launched last week were in the southern provinces of Ghazni, Helmand and Kandahar. All have seen intense Taliban activity in the past weeks.

"These operations are aimed at providing security in the area so the reconstruction can take place," General Mohammad Zahir told a news conference.

Operation "Kulang" (pickaxe), involving hundreds of Afghan troops and British forces operating under the Nato-led International Security Assistance Force (Isaf), was underway in districts of Helmand, Azimi said.

The offensive caused 60 Taliban fighters to flee across the Helmand River Friday, he said. Their boat sank and they were all killed, he said.

Two Afghan soldiers also died, Azimi said.

A similar offensive code-named "Hadalat," meaning justice, was launched in neighbouring Kandahar -- the former stronghold of the Taliban, Azimi said.

It involved Afghan and Canadian troops and US Special Forces.

In Ghazni province, hundreds of other Afghan and Isaf troops unleashed Operation Maiwand -- named after a troubled Kandahar district where the British were defeated by an Afghan army in 1880.

Four rebels have been captured since the launch of the offensive on Saturday, the general said.

The province has seen a spike in violence in the past few months, with a suicide bombing last month which killed 10 Afghans while militants killed five relatives of a policeman in an attack late Thursday.

A spokesman for the Taliban meanwhile called on Afghans Sunday to stay away from foreign military bases and convoys, warning of a wave of attacks on the troops.

"We call on Afghans to stay away from foreign forces because a big (Taliban) operation is due to be launched. This will include ambushes, suicide attacks and roadside explosions," Zabihullah Mujahed said.

"If any civilian gets hurt, it'll be their responsibility," he told AFP by telephone from an unknown location.

The Taliban insurgency was launched soon after the hardline, Islamic movement was driven from government in late 2001. It is said to have been joined by other Islamist militias, foreign fighters and opium traders.