The US military has withdrawn 10,000 troops from Afghanistan before a year-end deadline set by President Barack Obama, officers said Friday, the first step in a planned drawdown of combat forces through 2014.

The withdrawal left about 91,000 American troops on the ground in Afghanistan, spokesman Commander Bill Speaks told AFP.

Obama announced a surge of 33,000 forces in December 2009 to turn the tide in the war.

After declaring major progress against the Taliban insurgency, Obama has since promised to withdraw the reinforcements in two stages: 10,000 by the end of this year and another 23,000 by the end of next summer.

"They have met the first target of recovering 10,000 of the surge forces by the end of the year," Speaks said.

US and coalition partners in Afghanistan plan to hand over security for the whole of the country to Afghan forces by the end of 2014, allowing the withdrawal of combat forces.

US administration officials and military commanders are debating the pace of further troop withdrawals in 2013 but have already suggested the Afghan mission will shift from direct combat to an advisory role next year.