* Legal framework pact probably left for successor
* U.S., NATO forces could leave end-2014 if no deal
* Complete foreign withdrawal could jeopardise aid
By Adrian Croft
MUNICH, Feb 1 (Reuters) - President Hamid Karzai is unlikely to sign a pact for U.S. and NATO forces to stay in Afghanistan after 2014 and will probably leave the choice for his successor, NATO chief Anders Fogh Rasmussen said on Saturday.
Kabul and Washington spent months negotiating a legal framework for some U.S. troops to stay on after the end of 2014, when NATO-led forces are due to end combat operations, leaving behind a much smaller training and advisory mission.
But Karzai has said he will not sign the agreement unless certain conditions are met.
The delay has frustrated the United States and its allies, who want to plan the post-2014 training and advisory mission.
Both the United States and NATO have said they may be forced to pull their forces out of Afghanistan entirely at the end of this year unless the agreement is signed soon.
Rasmussen acknowledged for the first time on Saturday that he did not expect Karzai to sign the U.S. pact and a similar pact that must be negotiated with other NATO forces.
Instead, he believed Karzai would leave the issue for the president elected in April 5 election.
Karzai has served two terms and cannot run again.
"I think, realistically speaking, a new president will be the one to sign," Rasmussen told reporters during the annual Munich Security Conference.
He said however he was confident that Afghanistan would sign the agreement "at the end of the day" and NATO would still have time to plan its post-2014 mission, even if it was not signed until Karzai's successor was in office.
"Most probably, it will be for a new president to sign a security agreement and in that case we are prepared to stay after 2014," Rasmussen said.
"If we don't get a signature even from a new president, then we will also be prepared to withdraw everything by the end of 2014, because in that case we don't have a legal basis for a continued presence," he said.
The NATO-led force currently has around 57,000 soldiers in Afghanistan, two-thirds of them from the United States. Troop numbers are expected to fall to 8,000-12,000 after 2014.
Rasmussen has said a complete foreign military withdrawal from Afghanistan could also jeopardise foreign military aid needed to finance the 350,000-strong Afghan security forces as well as development aid.
The foreign aid totals about $8 billion a year.