REPUBLIKA.CO.ID, WASHINGTON - US President Barack Obama on Tuesday outlined a plan to withdraw all but 9,800 American troops from Afghanistan by the end of the year and pull out the rest by the end of 2016, ending more than a decade of military engagement triggered by the Sept. 11 attacks on the United States.

The decision means that Obama will leave office in early 2017 having extricated the country from the longest war in US history. He ended Washington's combat presence in Iraq in 2011.

Obama's White House Rose Garden announcement prompted criticism from Republicans that the hard-fought gains made against the Taliban could be lost in much the same way that sectarian violence returned to Iraq after the US withdrawal.

Obama, who made a whirlwind visit to US troops in Afghanistan over the weekend before American combat operations conclude at the end of 2014, appeared to anticipate concerns that he is abandoning Afghanistan. He said it is time for Afghans to secure their country.

"We have to recognize that Afghanistan will not be a perfect place, and it is not America's responsibility to make it one," Obama said.

Under his plan, 9,800 US troops would remain behind into next year. By the end of 2015, that number would be reduced by roughly half. 

By the end of 2016, the US presence would be cut to a normal embassy presence with a security assistance office in Kabul, as was done in Iraq. The 9,800 troops would take an advisory role backing up Afghan forces. 

They would train Afghan troops and help guide missions to rout out remaining al Qaeda targets. Any US military presence beyond 2014 is contingent on Afghanistan's government signing a bilateral security agreement with the United States. 

Outgoing Afghan President Hamid Karzai has refused to sign it. But US officials were encouraged that the two leading candidates in Afghanistan's presidential race, Abdullah Abdullah and Ashraf Ghani, have both pledged to sign quickly should they be elected in the second round of voting set for June 14.