KABUL: A roadside bombing killed three Afghan policemen in the country's south on Tuesday while a Nato service member died in an attack in eastern Afghanistan, officials said.

The three policemen died when their patrol vehicle struck a bomb planted along the road in the district of Bahrami Shahid in southern Ghazni province, according to the province's deputy police chief, Asadullha Ensafi.

A fourth policeman was wounded in the attack, Ensafi said.

There was no immediate claim of responsibility for the bombing but Ensaf blamed the Taliban, who frequently target the country's security forces.

Separately, Nato said one of its service members was killed in an attack in the east, also on Tuesday.

The US-led military alliance provided no other details. Coalition policy is for home countries to identify their military dead. The death brought to 51 the number of Nato service members who died in Afghanistan so far this year, including 38 Americans.

Casualties have been falling in the US-led military alliance as its forces pull back to allow the Afghan army and police to fight the Taliban insurgency. All foreign combat troops are scheduled to be withdrawn from Afghanistan by the end of this year.