The US Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, says the Iraqi government must act soon if it wants US forces to stay longer in the country.

Discussions have intensified in the Iraqi government, over whether to keep US troops past their deadline, which ends this year.

Admiral Mike Mullen, US Chairman of the Joint Chiefs of Staff, said, "I think the timeline is in the next few weeks because for the withdrawal there is what I call a physics problem. We've 47-thousand troops here, lots of equipment, and physically it just takes time to move them."