WASHINGTON - The Pentagon announced on Wednesday that US President Barack Obama had nominated a veteran of the Afghan war to command US and allied troops in Afghanistan.

If confirmed by the Senate, US Army Lt. Gen. John Nicholson would succeed Army Gen. John Campbell, who has served as commander in Afghanistan since the middle of 2014 and is expected to finish his term around March 1.

"For nearly 18 months, Gen. Campbell has given his all to the mission as our top commander in Afghanistan," Pentagon spokesman Peter Cook quoted US defense chief Ash Carter as saying at Wednesday's briefing.

Nicholson currently commands NATO's Allied Land Command, and had held several high-profile Army roles, including the commanding officer for the 82nd Airborne Division, and deputy commanding general for operations in Afghanistan from 2010 to 2012.

Currently, there are 9,800 US troops in Afghanistan who advise local security forces and conduct counter-terrorism missions.

In a major departure from his promise to bring all US troops home before leaving office, Obama announced last October he would keep 5,500 US troops in Afghanistan into 2017 and maintain the current 9,800 forces through "most of 2016."

During Wednesday, Cook said so far there had been no change in the drawdown plan though the pace of reducing down 9,800 troops to 5,500 "will be determined by commanders on the ground."