Afghan violence kills 21

Four British soldiers travelling in the country's north were also wounded when gunmen opened fired on them, witnesses and officials said.

The militants were killed by US-led coalition and Afghan troops, supported by attack helicopters and aircraft, in battles on Thursday and Friday in which an Afghan soldier also died, the coalition said.

Thirteen were shot dead in insurgency-hit Uruzgan province, where the soldier was killed, it said in a statement. A US soldier and an Afghan trooper were wounded but were in stable conditions.

US troops killed another militant in eastern Paktika province Friday when he and others were spotted allegedly trying to plant a bomb, the coalition said.

Patrolling soldiers "came across the four individuals placing improvised explosive devices in the middle of the road," it said in a statement.

"US forces killed one individual attempting to escape and captured two others," the statement said. The captured men were handed to Afghan police.

There are about 20,000 coalition troops in Afghanistan, most of them Americans, helping Afghan security forces root out Taliban and other insurgents waging a campaign against the government.

The insurgency was launched after the hardline Taliban were removed from government in a US-led operation in late 2001 because they did not hand over Osama bin Laden for the September 11 attacks.

The coalition force is mainly based in southern and eastern Afghanistan, the focus of the attacks, while a separate Nato-led International Security Assistance Force (ISAF) of about 10,000 soldiers patrols the capital and northern and western Afghanistan.

Four British soldiers with ISAF were wounded Saturday when gunmen opened fire on their vehicle in the relatively calm city of Mazar-i-Sharif, witnesses and ISAF said.

Attackers on a motorbike and in a car ambushed the unmarked ISAF vehicle in front of the city's famous Blue Mosque, witnesses said.

Onlookers captured four of the gunmen as they tried to flee and handed them to police, they said.

"Four UK soldiers have been injured and have been evacuated to receive medical treatment," ISAF spokesman Captain Michele Cortese said in Kabul.

Across the country, in southeastern Paktia province, a dozen men dragged two worshippers from evening prayers on Friday and shot them dead, district chief Mirza Mohammed told AFP.

They "killed them outside the holy place and they disappeared," he said.

The 12 attackers entered a mosque on Friday in southeastern Paktia province, some 120km southeast of Kabul, and grabbed two men who were saying their evening Ramadan prayers, district chief Mirza Mohammed told AFP.

"The armed men got the two worshippers out of the mosque, killed them outside the holy place and they disappeared," he said.

A tribal elder was shot dead inside another mosque in neighbouring Khost province on Wednesday, police said Saturday.

The attacks were the latest on the devout country's mosques during the holy month of Ramadan, with three pro-government religious leaders killed in various provinces mid-October and a district chief shot while praying.