Kabul - Afghan President Hamid Karzai Saturday condemned the killing of 76 civilians, mostly children, by a US airstrike in western Afghanistan, and vowed his government would take necessary measures to curtail such deaths in the future.

The US military acknowledged in a statement that it was aware of the government's allegations of civilian deaths in the operation against Taliban fighters Friday in the district Shindand of western Herat province.

"All allegations of civilian casualties are taken very seriously," the statement said. "An investigation has been directed."

Kabul - NATO forces coordinating with the Pakistan military fired artillery at militants who were preparing to attack a NATO International Security Assistance Force (ISAF) base in eastern Afghanistan, ISAF said on Friday.

Pakistani military confirmed to NATO forces that the militants were preparing to fire rockets at a military base in Paktika province, which is close to the porous border, ISAF said in a statement.

ISAF forces "gained positive identification of the insurgents" and fired "multiple artillery rounds" into Pakistan on Thursday night, it said.

Kabul - Three Canadian soldiers were killed and another was wounded in a roadside bombing in southern Afghanistan, officials said Friday.

The soldiers, who were serving under the NATO-led International Security Assistance Force (ISAF), were in a vehicle when it was struck Wednesday by the bomb in the Zherai district of Kandahar province, the Canadian military said.

London  - British Prime Minister Gordon Brown told British soldiers on a surprise visit to the British troop base Helmand in Afghanistan Thursday they were in the "front line in the fight against the Taleban".

Rejecting fears that the battle against the al-Qaeda linked Taleban was losing ground, he said: "You know that by what you are doing here you prevent terrorism coming to the streets of Britain."

Kabul  - British Prime Minister Gordon Brown arrived Thursday on a surprise visit to Afghanistan and was expected to meet Afghan President Hamid Karzai, an Afghan Foreign Affairs Ministry spokesman said.

During his one-day visit, Brown was scheduled to hold a joint press conference with Karzai Thursday in Karzai's fortified presidential palace, spokesman Sultan Ahmad Baheen said at a press conference.

Brown's visit to the war-torn country came a day after French President Nicolas Sarkozy came to Kabul after an attack on French soldiers killed 10 and wounded 21.

Kabul - Three Polish soldiers were killed in a roadside attack in southern Afghanistan, while Afghan and coalition forces claimed to have killed more than 30 Taliban militants in the east of the country, officials said Thursday.

The three soldiers were killed in a roadside attack in southern Afghanistan on Wednesday, the NATO-led International Security Assistance Force (ISAF) said in a statement.