Gunmen killed two American NATO troops Thursday in southern Afghanistan. Authorities believe one of the gunmen is an Afghan soldier.
Thursday's shooting is the latest retaliation by Afghan Muslims over the accidental burning of Koran at a U.S. military base.
President Obama and military leaders have apologized to the Muslim world for the unintended desecration of Islam's holy book.
When ABC News asked the president if the apologies had worked, he said "yes."
"It calmed things down," the president said, but added, "We're not out of the woods yet."
"The politics or the second guessing (of) these decisions, I'm not worried about," he said. "I'm worried about making sure that the men and women in uniform are in the best possible position to come home safely and carry out their mission."
Six NATO service members have been killed by Afghan security forces in less than two weeks.
Meanwhile, the leader of the United Nations mission in Afghanistan is calling for "disciplinary action" for the U.S. troops involved in the Koran burning incident.