NATO soldiers inspect the wreckage of a car used by a suicide bomber in an attack on a NATO convoy in Kabul, Afghanistan, on Monday. (Rafiq Maqbool/Associated Press)

A suicide bomber rammed his car into a NATO convoy in Kabul on Monday, killing three civilians and wounding at least a dozen, officials said.

Clashes and an airstrike in the south killed 25 militants and eight civilians held hostage by insurgents.

Another bomb attack against a NATO convoy in the country's northwest wounded 14 people, mostly civilians.

The Kabul suicide bomber targeted a NATO convoy on the main road in the city's eastern outskirts, killing three civilians and wounding 12 others, said Ayub Salangi, the provincial police chief.

The blast also wounded some NATO soldiers, NATO's press office in Kabul said. An eyewitness who was travelling ahead of the convoy when the blast happened said the troops were British.

"I turned my head and saw a big burst of fire next to my car," said Ahmed Shakeb, 22. "I saw that the convoy was British."

Taliban spokesman Zabiullah Mujahed claimed responsibility for the blast, and said a man named Aminullah from the eastern province of Khost blew himself up. Mujahed's claim could not be independently verified.

U.S.-led forces kill 8 civilians

In the southern province of Uruzgan, meanwhile, militants ambushed U.S.-led and Afghan troops along a road Sunday, triggering gun battles during which militants moved in to a compound and took 11 civilians hostage, a statement for the U.S.-led forces said.

"Troops called in close-air support to engage the militants hiding in the structure. They did not have knowledge of non-combatants in the buildings at that time," the U.S.-led forces' statement said.

As a result, eight civilians were killed and three were wounded, the statement said. The wounded civilians were taken to a base for treatment.

U.S. Lt. Nathan Perry said the three civilian hostages who survived the airstrike in Uruzgan included an infant, a man in his 40s and a woman in her 20s.

Juma Gul Himat, the provincial police chief, said six civilians — one child and five men — were killed and three others were wounded in the strike. He could not immediately explain why the military said eight civilians were killed.

Himat blamed the Taliban fighters for using civilians homes for cover during the attack, thus putting civilians in danger. NATO regularly accuses militants of commandeering civilian homes and using them to attack foreign and Afghan troops.

But Afghan President Hamid Karzai and other officials in Kabul have pleaded with the coalition to avoid killing civilians, which threatens to undermine support for the government. Karzai on Sunday urged the U.S.-led coalition and NATO troops to go after militant sanctuaries in Pakistan, rather than bomb Afghan villages.

"The struggle against terrorism is not in the villages of Afghanistan," Karzai said. "The only result of the use of airstrikes is the killing of civilians. This is not the way to wage the fight against terrorism."

More than 3,000 people — mostly militants — have died in insurgency-related violence this year, according to an Associated Press tally of figures from Western and Afghan officials.

Bomb attack

In the northwestern province of Faryab on Monday, a bomb attack wounded 14 people, including two foreign soldiers and 12 civilians, said Khalil Andarabi, the provincial police chief.

A convoy was passing through the centre of the provincial capital at the time of the explosion, Andarabi said. The bomb was placed on a motorbike on the side of the road and was remotely detonated, he said.

NATO confirmed the attack but did not provide further details. Many of the alliance's troops in Faryab are Norwegian.

The attacks come at a time of an increased insurgent activity throughout the country. The number of insurgent attacks in the first six months of 2008 were over 50 per cent higher compared with the same period last year, according to an Afghan security group that advises foreign aid agencies.

Militants regularly target foreign and Afghan troops with suicide and roadside bombings, but the majority of the victims in those attacks are civilians.

In other violence reported Monday, militants ambushed a convoy of vehicles belonging to a demining company in the southern province of Zabul, killing two Afghan guards and wounding seven others, said Jalani Khan, a police official.

Afghanistan is one of the world's most heavily mined countries after suffering through decades of war. Demining teams have been working around the country to clear minefields since the Taliban's ouster in 2001.