With less than four months remaining before the U.S. election, Obama's tour, set to include stop-offs in Jordan, Israel, France and Britain, has sparked media attention around the world.
The foreign trip is seen as a response Republican rival John McCain's claim that Obama lacks the experience to be the U.S. commander in chief, a view backed up by opinion polls in the country. McCain has also criticized Obama for having visited Iraq only once.
Speaking to reporters on Thursday, the Illinois senator said: "I'm looking forward to seeing what the situation on the ground is... I want to 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."
On his planned meeting with Afghan President Hamid Karzai, he said: "I'm more interested in listening than doing a lot of talking... I think it is very important to recognize that I'm going over there as a U.S. senator. We have one president at a time, so it's the president's job to deliver those messages."
Obama had not previously visited Afghanistan, which he has singled out as a foreign policy priority, with the Taliban increasing its hold on the country seven years on from the U.S.-led invasion that ousted the Islamic group's regime.
In Europe Obama is scheduled to meet with German Chancellor Angela Merkel, British Prime Minister Gordon Brown, and French President Nicolas Sarkozy, all of whom will be careful not to be seen as taking sides in the U.S. presidential race.
The Democratic presumptive nominee's visits to Iraq and Afghanistan are part of a congressional delegation tour, while the stop-offs in Israel, Jordan, London, Berlin, and Paris are part of Obama's pre-election campaign, which has already raised a record volume of funds.
