"This is part of the President's goal and strategy of having sustainable partners around the world where terrorist threats could emerge," said Lisa Monaco, deputy national security advisor and assistant to the President for homeland security and counter terrorism, during a conference call.
Senior administration officials insisted that the continuing to have 9,800 US troop till the end of 2016 and 5,500 after that does not mean any change in the American mission in Afghanistan.
At the same time, Monaco argued that one of the main role of the 5,500 troop at various bases in Bagram, Jalalabad and Kandahar would be to go after al-Qaeda, which is gaining strength after Pakistan in their recent operation pushed them across the Afghan border.
"They will be focused on the two missions: going after Al-Qaida and terrorist threats that emerge; and making sure that we don't have a resurgence of al-Qaida. Due to military efforts by the Pakistanis, there has been displacement of al-Qaida into Afghanistan," she said.
"We're obviously concerned and watching carefully the emergence of militants who want to affiliate with ISIL, but we have a national security interest in making sure that there can't be a safe haven in Afghanistan. So the 5,500 troops are going to be able to support our counter-terrorism operations," Monaco added.
"But importantly, they're also going to work with our Afghan partners in very targeted ways in terms of identifying places where we can provide a maximum amount of training, advice and assistance. So for instance, with the Afghans' air operations and working with their special forces," she said.
Laurel Miller, the acting special representative for Afghanistan and Pakistan, said that the US expects its other allies including its NATO partners to have maintain additional troops.