"This is where you start to hear concerns that you're not seeing the results that were hoped for, which perhaps were unrealistically expected."
Faced with opposition from senior Democrats and a pessimistic assessment from his top military commander, Obama is reassessing a military strategy for Afghanistan that he approved in March.
A key challenge will be to show progress on restarting Mideast peace talks. After months of effort to wrest concessions from Israel, Palestinians and Arab nations, U.S. envoy George J. Mitchell returned empty-handed last week from his latest visit to the region.
Partly as a result, Obama shifted his administration's emphasis on the divisive issue of Jewish settlements in the West Bank. Though he previously demanded that all construction of settlements be halted, he called on Israel this week to "restrain" settlement growth and said the issue should not be a barrier to peace talks.
Obama urged the Israeli and Palestinian leaders at a three-way meeting in New York to move quickly to revive negotiations.
By sweeping the settlement issue off the table for now, Obama handed a tactical victory to Israeli Prime Minister Benjamin Netanyahu, who had insisted on peace talks without preconditions or a predetermined timetable and agenda.
"The government has shown that you don't always need to get flustered, to surrender and give in," Israeli Foreign Minister Avigdor Lieberman told Israel Radio.
But in his speech Wednesday, Obama said the administration's stance on the Jewish settlements had not changed.
"America does not accept the legitimacy of continued Israeli settlements," he said.
Palestinian Authority President Mahmoud Abbas had refused to meet with Netanyahu without the promise of a construction halt, but relented when Obama summoned both leaders to Tuesday's session in New York.
A former legal advisor to the Palestinian Authority, Diana Buttu, said it would be difficult for Abbas to reject Obama's appeal to resume talks as soon as possible. But Jibril Rajoub, a senior leader in Abbas' Fatah movement, warned of failure if Netanyahu allowed settlements to keep growing.
"If he wants to push us into a corner, then I think he will drive us all into a wave of violence and bloodshed," Rajoub said.
Times staff writer Richard Boudreaux in Jerusalem contributed to this report.