President Barack Obama departed late Thursday for a NATO summit in Portugal where allied leaders will take up the bogged down war in Afghanistan.
Air Force One departed from Andrews Air Force Base in Maryland at 11:47 pm (0447 GMT) with the president and his entourage, according to White House pool reports.
He was scheduled to arrive in Lisbon at 10:50 am local time (0950 GMT).
The two-day summit is expected to back a 2014 target date for turning over responsibility for security of Aghanistan to the government in Kabul.
Mr Obama will meet with Afghan President Hamid Karzai on the sidelines of the summit, the White House said.
The US president also will meet one-on-one for the first time with Georgia's President Mikheil Saakashvili, who has had distant relations with Washington as Mr Obama has sought to reset relations with Russia.