KABUL (AFP) - Democratic presidential hopeful Barack Obama met US troops in Afghanistan Saturday during a visit to assess efforts against extremist militants at the start of a major international tour, officials said. US military commanders at the main US base at Bagram, north of Kabul, briefed Obama and other senators on the international efforts against Taliban and other extremists, the US-led coalition said. The delegation later flew to a base in eastern Afghanistan, closer to the border with Pakistan, where they met more of the 36,000 US soldiers in Afghanistan. Obama was due to hold talks with President Hamid Karzai on Sunday, the Afghan government said. The presumptive Democratic presidential nominee told reporters before leaving the United States that he was looking forward during his trip, which will also take him to Iraq, to seeing the situation on the ground. "I want to, obviously, talk to the commanders and get a sense, both in Afghanistan and in Baghdad of, you know, what their biggest concerns are. And I want to thank our troops for the heroic work that they've been doing." The Illinois senator said in the days building up to the tour that Afghanistan needs more help as it battles the Taliban-led insurgency. If he wins the November elections, he has said he would commit at least two more combat brigades, up to 10,000 men, to Afghanistan while downscaling the size of the force in Iraq. "We need more troops, more helicopters, better intelligence-gathering and more non-military assistance to accomplish the mission there," Obama said in The New York Times on Monday. "Iraq is not the central front in the war on terrorism, and it never has been." In a radio address Saturday, his Republican rival John McCain criticised Obama for announcing his strategy for Afghanistan and Iraq before his fact-finding tour. "Apparently, he's confident enough that he won't find any facts that might change his opinion or alter his strategy " remarkable," McCain said.