updated 1:15 a.m. ET July 20, 2008

KABUL, Afghanistan - Barack Obama visited with U.S. troops and Afghan officials at the start of a Europe and Mideast trip aimed at bolstering his foreign policy and national security credentials and countering Republican claims that he is not ready to be commander-in-chief.

Along the way, he got heavy criticism from his Republican rival, Sen. John McCain, and indirect support from an unlikely quarter, Iraqi Prime Minister Nouri al-Maliki.

Obama's first overseas tour since securing the Democratic nomination last month could be key to honing his foreign policy strategy with less than four months before the election. McCain, has criticized Obama for not spending more time in the region and for developing a policy without more firsthand knowledge.

Obama met for breakfast with U.S. troops on Sunday and was to meet with Afghan President Hamid Karzai as part of a congressional delegation.

At breakfast, Obama and the other senators traveling with him met with soldiers and sailors from their respective constituencies, said Lt. Col. Dave Johnson, a U.S. military spokesman.

"The food was great, but the company was better," Johnson said.

While officially part of a fact-finding tour expected to take him to Iraq, Obama arrived Saturday amid the publicity and scrutiny accorded a likely Democratic nominee for president rather than a senator from Illinois. Security was tight and media access to Obama was limited by his campaign; his itinerary in the war zones was a closely guarded secret.

Obama and others in the delegation received a briefing inside the U.S. base in Jalalabad from the Afghan provincial governor of Nangarhar, Gul Agha Sherzai, a former warlord.

"Obama promised us that if he becomes a president in the future, he will support and help Afghanistan not only in its security sector but also in reconstruction, development and economic sector," Sherzai told The Associated Press.

The area where the meeting took place is not far from where Osama bin Laden escaped U.S. troops in 2001 after his al-Qaida terrorist group led the Sept. 11 terrorist attacks in the U.S.

With the ousted Taliban regime resurgent and given the al-Qaida goal of terrorizing the U.S., Obama has argued that the war in Afghanistan deserves more attention as well as more troops.

Video   Obama stresses Afghan security July 19: On his first visit to Afghanistan, Barack Obama is focusing on the nation’s security. NBC’s Richard Engel reports. Nightly News

He has proposed sending two more combat brigades — about 7,000 troops — to Afghanistan. McCain is also advocating sending more forces to the war-battered country.

In his weekly radio address Saturday, McCain, a former Navy pilot and Vietnam prisoner of war, insisted his "many years of military and political experience" made him better suited to lead the U.S. to victory in Iraq and Afghanistan.

"In a time of war, the commander-in-chief's job doesn't get a learning curve," the veteran Arizona senator said.

McCain also chided Obama for giving a speech announcing "his strategy for Afghanistan and Iraq before departing on a fact-finding mission" to both countries.

"Apparently, he's confident enough that he won't find any facts that might change his opinion or alter his strategy. Remarkable," McCain said.

Traveling with Obama were Sens. Chuck Hagel, a Nebraska Republican, and Jack Reed, a Democrat from Rhode Island. Both military veterans, the senators have been mentioned as potential Obama vice presidential running mates, although Reed has said he is not interested in the job and Hagel would be an unlikely cross-party choice.

At the start of their Afghan trip, the delegation met with top military leaders and troops at Bagram Air Field, the main U.S. military base north of the capital, before going to Jalalabad.

Obama advocates ending the U.S. combat role in Iraq by withdrawing troops at the rate of one to two combat brigades a month. He supports increasing the military commitment to Afghanistan, where the Taliban-led insurgency is at its strongest in seven years.

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