In a bloody two days for foreign forces, another four NATO troops were killed in two separate attacks on Sunday by insurgents in the country's violent east and south, said the coalition.

The majority of foreign troops serving in those regions are American, although some French troops are also based in volatile Kapisa province in the east.

The French president's office in Paris said two French soldiers were killed and five wounded when they were attacked by insurgents in Kapisa's remote Tagab valley. There was no immediate confirmation of the nationalities of the other two.

"The head of state expresses again France's determination to continue to work with the International Security Assistance Force (ISAF) to restore peace and stability in this country and contribute to its development," the president's office said in a statement. Thirty US soldiers - some from the Navy's special forces SEAL Team 6, the unit that killed al Qaeda leader Osama bin Laden - seven Afghans and an interpreter died in Friday night's crash, just two weeks after foreign troops began a security handover to Afghan forces.

The Taliban quickly claimed responsibility for bringing down the helicopter with a rocket-propelled grenade. Although it often exaggerates incidents involving foreign troops, a US official in Washington said the helicopter was believed to have been shot down. NATO-led ISAF confirmed the death toll overnight, which was first announced by Afghan President Hamid Karzai, and said the cause of the crash was still being investigated.