Pakistan is to reopen crucial supply routes to Nato-led forces in Afghanistan after Washington apologised for killing 24 of its soldiers in November, the US has announced.

US Secretary of State Hillary Clinton said: "We are sorry for the losses suffered by the Pakistani military."

Pakistan has not yet commented on the US statement.

The routes are increasingly important as Nato prepares to withdraw all combat troops from Afghanistan in 2014.

The row over the supply lines has been hugely damaging to relations between Pakistan and the US.