US troops killed in Afghan blast

Four US soldiers have been killed by a roadside bomb in southern Afghanistan, Nato-led forces have said.

Two of the servicemen died in the blast on Thursday, and two others died later from their wounds.

Further details about the victims and the precise location of the attack have yet to be released.

This year has seen the greatest number of allied casualties in Afghanistan since US-led operations to oust the Taliban regime began in late 2001.

The latest deaths come as US President Barack Obama considers future troop options as part of a review of US strategy in Afghanistan.

Gen Stanley McChrystal, the commander of international forces in Afghanistan, is thought to have requested up to 40,000 more troops to help stabilise the country.

Separately on Friday, Nato said a woman and a girl had been accidentally killed in cross-fire during a battle with insurgents in the central province of Ghazni.

It said two militants were also killed, but it was unclear who was responsible for the civilian deaths.