BAGRAM AIR BASE (AFP) - US President Barack Obama on Friday paid a surprise lightning visit to Afghanistan to consult leaders and greet troops as he takes a hard look at whether his war strategy is working. Obama left the White House quietly and flew to Kabul under cover of darkness. It was the second such visit since Obama became president, with his aides announcing nothing of his trip beforehand due to security concerns. Obama , who has tripled US troop numbers in Afghanistan, was spending a mere three hours in the country at Bagram Air Base, the headquarters of the 101st Airborne Division. Sporting a leather bomber jacket, Obama was met by General David Petraeus, commander of US troops in Afghanistan, and US ambassador Karl Eikenberry. He went straight to a base hospital to meet wounded soldiers spending the holiday season on the battlefront. White House officials, pointing to winds of more than 70 kilometers an hour, said Obama curtailed an original trip planned for up to six hours and will not take the short helicopter ride into Kabul. Instead, Obama spoke by telephone with President Hamid Karzai after technical problems with a videolink, aides said. White House spokesman described the Kabul weather as windy and cold. A spokesman for Karzai said that a joint press conference was cancelled because of bad weather. However, an AFP correspondent in Kabul reported clear skies in the evening after a sunny and cloudless day. Obamas trip comes as his administration faces new friction with Karzai over embarrassing assessments of him in leaked diplomatic cables. The Obama administration is working on a review of its war strategy to be completed before the president leaves for holidays in late December. White House aide Ben Rhodes told reporters on Air Force One there was no major new piece of news that Obama would bring into his meeting with Karzai but that he would glean information for the December review. Its not about that, Rhodes said, calling the visit more about thanking the troops. Rhodes said the White House began preparing the Kabul visit more than a month ago as Obama wanted to visit US troops and civilians in Afghanistan between Thanksgiving and Christmas. Basically to wish them happy holidays. Its a particularly tough time of year, Rhodes said. Obama on Friday told US troops you will succeed in your mission, and stressed they were breaking the momentum of the Taliban. Youre achieving your objectives, you will succeed in your mission, Obama told more than 3,000 exuberant soldiers gathered at Bagram Air Base. We said we were going to break the Talibans momentum. Thats what youre doing, he said after touching down at the air base outside Kabul. But Obama , on his second trip as president to the war-torn country, warned there are going to be difficult days ahead in the fight against insurgents, and appeared to choke up as he described a visit to a base hospital where he pinned Purple Hearts on wounded soldiers. I dont need to tell you this is a tough fight, the commander in chief said. I just came from the medical unit and saw our wounded warriors. I just talked to the platoon that lost six of their buddies in a senseless act of violence. Its a tough business, he said. Progress comes slow. But he stressed to the troops, most from the 101st Airborne Division currently headquartered at the base, that today we can be proud that there are fewer areas under Taliban control, and more Afghans have a chance to build a more hopeful future. The administration is meanwhile working on a review of its war strategy to be completed before the president leaves for holidays in late December. Obama assured troops that support for them was rock solid, despite misgivings among Americans about the war and its mission. Even though it is a hallmark of American democracy that we have our arguments back home... I can say without hesitation, theres no division, no hesitation on one thing: that is the uniform support of men and women serving in the armed services.