Two civilians have been killed and 10 injured after a missile fired by a Nato-led coalition aircraft missed its target in eastern Afghanistan and struck a house, alliance officials have said.

Nato said they were aiming at a "militant position" in the province of Khost on Tuesday when the missile "malfunctioned" and fell more than 2.5 km from the target.

The deaths came as George Bush, the US president, announced 4,500 extra US troops would be sent to Afghanistan by January.

The US currently has 33,000 troops in Afghanistan, split between a Nato-led mission and a separate "counter-terrorism" mission run by the Pentagon.

Civilian deaths

Afghans have been angered by the high numbers of civilians killed and injured by US- and Nato-led raids in recent weeks and the government has urged a review of foreign combat operations.

A report by Human Rights Watch (HRW), a New York-based rights organisation, said in 2006, 230 civilians died during US or Nato attacks out of a total of 929 Afghans in the conflict that year.

In 2007, HRW said 321 were killed by US or Nato air attacks, and in 2008 so far, almost 130 people have been killed.