Seven US soldiers and a member of the NATO-led coalition were killed in one of the deadliest days for Americans and other foreign troops in Afghanistan in recent months, as the Taliban continued attacks as part of their spring offensive.

The renewed violence came on Saturday as Afghan President Hamid Karzai acknowledged at a news conference that regular payments his government has received from the CIA for more than a decade would continue.

Karzai also said that talks on a US-Afghan bilateral security agreement to govern future American military presence in the country had been delayed because of conditions the Afghans were placing on the deal.

The US-led coalition reported that five international troops were killed by a roadside bomb in southern Afghanistan, and coalition spokesman Capt Luca Carniel confirmed that all five were American.

The coalition did not disclose the location of the roadside bombing. However, Javeed Faisal, a spokesman for the governor of Kandahar province, said the coalition patrol hit the bomb in the Maiwand district of the province, the spiritual birthplace of the Taliban.

Later, the coalition reported that a soldier with the Afghan National Army turned his weapon on coalition troops in the west, killing two in the most recent of so-called insider attacks.

Such attacks by members of the Afghan security forces against their fellow colleagues or international troops have eroded confidence in the Afghan forces as they work to take over from foreign forces.

Both killed were American, according to two US officials who spoke on condition of anonymity to disclose the nationalities ahead of an official announcement.

Another coalition service member was killed in an insurgent attack in northern Afghanistan, the NATO-led force said.

It did not provide any further details of the incident. It was the fourth time since last summer that seven Americans have been killed on a single day in the war.