"What we're looking for is a comprehensive strategy [for Afghanistan]," President Obama told the CBS programme 60 Minutes on Sunday.
"There's got to be an exit strategy. There's got to be a sense that this is not a perpetual drift."
He also warned that the focus of US policy should remain on eliminating direct terrorist threats to the US: "Making sure that Al Qaeda cannot attack the US homeland and US interests and our allies. That's our number one priority."
Agence France-Presse highlighted Obama's remarks that the "decision last month to send 17,000 more US troops to Afghanistan – largely to head off a spike in violence before elections in August – was the most difficult he has had to make since taking office."
"You know I think it is the right thing to do. But it's a weighty decision because we actually had to make the decision prior to the completion of (the) strategic review that we were conducting," he said.
US commanders have said as many as 30,000 additional troops are needed to overcome a stalemate in parts of Afghanistan. But some analysts caution against a gradual Vietnam-like escalation in a country historically hostile to outsiders.