ANTI-US PROTEST: Supporters of the Islami Jamiat Talaba party burning a US flag during a protest in Multan against US and Coalition forces, yesterday. A Pakistani paramilitary soldier was killed and two wounded on Monday in cross-border fire from US-led coalition forces in Afghanistan who apparently mistook the troops for militants, officials said. (REUTERS)

ISLAMABAD • Pakistan formally protested to the United States and Britain yesterday over cross-border fire by international forces in Afghanistan that killed one of its soldiers and wounded two.

The foreign forces apparently mistook Pakistani paramilitary troops in their traditional shalwar and kameez tunics for militants and fired on them at Zangota checkpost in the North Waziristan tribal region on Monday.

Summoned to the Foreign Ministry in Islamabad, the American and British ambassadors were told "the coalition authorities should investigate the incident and ensure that such incidents do not occur in future", the ministry said in a statement.

"Both expressed deep regrets and said that the incident was being investigated." Afghanistan's Nato force said the incident happened following an insurgent rocket attack near a Nato base on the border. "Shortly afterwards a group of insurgents was identified moving east towards the Pakistan border," Nato said.

A Nato aircraft attacked the insurgents and Nato said it believed "all ordnance fired landed on the target and one insurgent was killed and another injured".

"Isaf deeply regrets the loss of life and injuries sustained by Pakistani forces, although the cause of these casualties, and who is responsible, is as yet unclear," the Nato force, known as the International Security Assistance Force, said in a statement.

A joint Nato-Pakistani investigation had been convened, it said.

Pakistan is a key ally in the US-led war on terrorism but the United States and other western countries have been urging it do more to curb growing cross-border infiltration by militants from its territory.

This month, Nato and Afghan forces killed about 130 militants in a ground and air attack in southern Afghanistan after they infiltrated from Pakistan.

Pakistan acknowledges that some militants are slipping into Afghanistan, but says the insurgency is mainly an Afghan problem, feeding on poverty and anger with the government over corruption.