Barack Obama visited U.S. troops and talked to government officials as he toured war-weary Afghanistan Saturday. The country is a key part of the anti-terror strategy that he has proposed to implement if elected president.

The presumptive Democratic presidential nominee is trying to boost his foreign affairs credentials with visits to Europe and combat zones involving the U.S. military. Obama flew to eastern Afghanistan, where he and a U.S. congressional delegation were to visit American soldiers stationed in the region.

Security was extremely tight for the visit as media access to Obama was limited, and his itinerary in the war zones was a closely-guarded secret.

Obama, along with others in the delegation, had a briefing inside the U.S. base in Jalalabad from the provincial governor of Nangarhar, Gul Agha Sherzai, a bullish 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.

Obama is expected to meet with Afghan President Hamid Karzai Sunday.

Michael Kergin, a former Canadian ambassador to the United States told Â鶹´«Ã½net that the biggest risk for Obama in Afghanistan was if "he misspeaks or acts if he is the presumptive president as opposed to being just a candidate."

Obama has proposed sending two more combat divisions to Afghanistan, about 7,000 soldiers in all.

Kergin said that Obama should find support from the U.S. public in stepping up efforts in Afghanistan.

His Republican rival, John McCain has questioned and criticized Obama's foreign policy credentials. He had noted the Illinois senator had not previously gone to Afghanistan.

McCain has also pushed for more troops for the increasingly deadly mission in Afghanistan.

Democratic strategist Maryscott Greenwood told Â鶹´«Ã½net the trip is a "high risk" venture. But she noted, it also offers the potential of "high rewards."

She said Obama must use the trip to reassure voters about his international policies.

Obama has articulated a vision in direct contrast to what the Republicans are saying ... If he's going to be talking about Afghanistan, he certainly had to go there," Greenwood said.

Kuwait trip

Before leaving for Afghanistan, Obama visited U.S. forces in Kuwait.

"He talked to soldiers and constituents and met with senior military leadership," said Lt. Col. Bill Nutter, a spokesman for the U.S. military in Kuwait.

Obama was given an overview of operations, and then posed for photos with soldiers and answered questions.

Obama has repeatedly criticized McCain and U.S. President George Bush for their Iraq policies. He has said the war in Iraq should never have been started and has made the U.S. less safe. He had come out against the war in Iraq before it was waged in 2003.

He has called on the U.S. to leave Iraq and focus its attentions on fighting the insurgency in Afghanistan. Obama has also criticized Iraqi and Afghani leaders, saying they need to step up and take control of their own security and political situations.

Sens. Chuck Hagel and Jack Reed -- both considered possible, although unlikely, Obama vice presidential running mates -- are also on the tour.

With files from The Associated Press