U.S. Defense Secretary Chuck Hagel arrived on an unannounced visit to Afghanistan.
Hagel, speaking to reporters in Kabul, said Afghanistan had "come a long way" over the past decade and that he had confidence in the Afghan security forces to fend off the Taliban after NATO's withdrawal this year.
Hagel, who is to step down from office, is expected to meet with senior Afghan officials.
President Barack Obama on December 5 named Ashton Carter, a technocrat with long experience working in the Pentagon, to replace Hagel.
Hagel's visit came as three police officers were killed in a Taliban attack in the northern province of Jawzjan.
The Taliban, who claimed resposnbility for the December 6 attack, have stepped up their attacks targeting local police and Afghan security forces.
Based on reporting by Reuters, AP, and AFP
