Kabul - A soldier under NATO command and three Afghan policemen were killed in two different incidents in southern Afghanistan, while unknown gunmen killed an Islamic cleric in the same region, officials said Tuesday.

The soldier, who was part of NATO-led International Security Assistance Force (ISAF), was killed in a "hostile incident" in the southern region on Tuesday, ISAF said in a statement.

The statement did not reveal the identity or nationality of the deceased soldier, nor did it say how the incident occurred. Most of the 50,000-strong ISAF troops in the south are soldiers from the US, Canada and Britain.

Separately, Taliban fighters attacked a police checkpoint in Dand district of southern Kandahar province on Monday, killing three officers and wounding another, said Gholam Ali Wahdat, police commander for the southern region.

Another three police officers were missing following the attack that took place on the western outskirts of Kandahar city, he said.

Also on Monday, two gunmen riding on a motorbike shot to death an Islamic cleric inside a mosque in Kandahar city after an evening prayer, Zelmai Ayoubi, spokesman for the provincial governor, said.

The motive behind the murder was not immediately known. Taliban militants have killed several Muslim scholars on charges of supporting the Western-backed Afghan government.

Despite the onset of harsh winter conditions, Taliban-led violence is plaguing southern and eastern regions of the country. Last year the militants staged bloody insurgency warfare that marked the most violent period since the fall of Taliban fundamentalist regime in late 2001.

The conflict in 2008 left thousands of people - mostly insurgents, but also more than 290 international soldiers - dead. (dpa)