Three international troops were killed in separate insurgency incidents in Afghanistan in one day, the NATO-led coalition force said.

The International Security Assistance Force (ISAF) said one service member was killed by an improvised explosive device in the south of the country, one by a similar blast in the east and one by an insurgent attack in the east.

All three incidents happened on Tuesday, with the last statement released on Wednesday. They did not give further details.

"It is ISAF policy to defer casualty identification procedures to the relevant national authorities," each statement said.

ISAF has around 130,000 troops in Afghanistan fighting the Taliban-led insurgency against President Hamid Karzai's government and its Western allies. Most foreign soldiers are due to be withdrawn by the end of 2014.