UPDATE 3-Obama begins foreign tour in Afghanistan

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By Jon Hemming

KABUL, July 19 (Reuters) - U.S. Democratic presidential candidate Barack Obama arrived in Afghanistan on Saturday, on the first leg of a trip aimed at proving his foreign policy credentials that will also take in the Middle East and Europe.

Obama's trip to Afghanistan, Iraq, Jordan, Israel, Germany, France and Britain is meant to prove he can credibly navigate the minefield of international diplomacy and answer critics who say he is too inexperienced for the task of commander-in-chief.

Just before boarding a military plane for the trip, Obama told reporters he expected to do a lot of listening.

"I want to, obviously, talk to the commanders and get a sense, both in Afghanistan and in Baghdad of ... what ... their biggest concerns are. And I want to thank our troops for the heroic work that they've been doing," Obama said.

He wants to send two more brigades, or about 7,000 U.S. troops, to Afghanistan and a shift from what he called the Bush administration's "single-minded" focus on Iraq. He has called for removing U.S. combat troops from Iraq in 16 months.

Iraqi Prime Minister Nuri al-Maliki said whether Obama or his Republican rival John McCain won the Nov. 4 election, pulling out troops in the shorter term would be better for Iraq.

Asked in an interview with Germany's Der Spiegel magazine when U.S. troops should leave Iraq, he said: