BAGRAM AIR BASE: US President Barack Obama landed in Afghanistan on Sunday for a surprise Memorial Day weekend visit with US troops to thank forces who are preparing to withdraw after nearly 13 years of war.

Spirited out of Washington aboard Air Force One Saturday night, Obama flew for more than 13 hours for the brief visit of several hours to Bagram Air Base, the main US base in Afghanistan, where he was to receive a military briefing, speak to the troops, and visit wounded soldiers in a hospital.

Obama, making his fourth trip to Afghanistan, arrived at Bagram on Sunday night local time. He brought country music star Brad Paisley with him to provide entertainment for the troops.

Obama's Afghan visit is bound to be seen by some critics as an attempt to redeem himself in the eyes of military veterans who are alarmed at allegations that government-run medical facilities in the United States did not provide timely care for veterans.

A pool of White House reporters and photographers accompanied the president under the strict condition that they not report on the trip until authorized, due to security considerations.