KABUL, Afghanistan — Democratic presidential contender Senator Obama started a campaign-season tour of combat zones and foreign capitals, visiting with American forces in Kuwait and then Afghanistan — the scene of a war he says deserves more attention and more troops.

The Illinois senator arrived today at Kabul as part of an official congressional delegation and then flew to eastern Afghanistan. Staff. Sergeant David Hopkins said Mr. Obama and two other senators were making a brief stop at Jalalabad airfield, in Nangarhar province, to visit with soldiers stationed there.

Mr. Obama’s first visit to Afghanistan, coming less than four months before the general election, was rich with political implications. Republican presidential rival Senator McCain has criticized Mr. Obama for his lack of time in the region. Mr. Obama is also expected to stop later in Iraq.

A campaign spokesman, Robert Gibbs, said Mr. Obama arrived at Kabul around noon. En route from Washington, he made a stopover at Kuwait to meet with American forces stationed there, Mr. Gibbs said.

A spokesman for Afghanistan’s Foreign Ministry, Sultan Ahmad Baheen, confirmed the senator was in Afghanistan and that he would meet with President Karzai.

“I look forward to seeing what the situation on the ground is,” Mr. Obama told a pair of reporters who accompanied him to his departure from Andrews Air Force Base on Thursday. “I want to, obviously, talk to the commanders and get a sense both in Afghanistan and in Baghdad of, you know, what the most, their biggest concerns are, and I want to thank our troops for the heroic work that they’ve been doing.”

Underscoring the challenges in Afghanistan, authorities reported today that a roadside bomb killed four policemen in the volatile south of the country where the Taliban-led insurgency is intensifying nearly seven years after a American-led invasion ousted the militant movement from power.

Mr. Obama advocates ending the American combat role in Iraq by withdrawing troops at the rate of one to two combat brigades a month. But he supports increasing the military commitment to Afghanistan, where the Taliban has been resurgent and Osama bin Laden is believed to be hiding.

Mr. Obama recently chided Mr. Karzai and his government, saying it had “not gotten out of the bunker” and helped to organize the country or its political and security institutions.

Also on his itinerary later in the trip is a meeting with the Iraqi leader, Prime Minister al-Maliki. On the campaign trail, Mr. Obama has said one benefit of withdrawing American troops is that it would pressure Mr. al-Maliki to shore up his government as well.

Nonetheless, he said he did not plan to reiterate those messages in person.

“I’m more interested in listening than doing a lot of talking, and I think it’s very important to recognize that I’m going over there as a U.S. senator,” he said. “We have one president at a time.”

The duration and details of Mr. Obama’s stay in Afghanistan have not been formally disclosed, and media access was limited.

Traveling with Mr. Obama were Senators Hagel, a Nebraska Republican and Reed, a Democrat from Rhode Island. The senators, both military veterans, have been mentioned as potential Obama vice presidential running mates, but Mr. Reed has said he’s not interested in the job.

In a speech this week, Mr. Obama said the war in Iraq was a distraction, unlike the fighting in Afghanistan.

“This is a war that we have to win,” he said. “I will send at least two additional combat brigades to Afghanistan, and use this commitment to seek greater contributions — with fewer restrictions — from NATO allies.

“I will focus on training Afghan security forces and supporting an Afghan judiciary, with more resources and incentives for American officers who perform these missions.”

By contrast, his opposition to the war in Iraq — and call for an end to the American combat role — helped him overcome his rivals in the battle for the Democratic presidential nomination.

Lately, his efforts to explain how he will use what he learns from American commanders to refine his proposals have brought charges from Republicans and complaints from Democratic liberals that he seems to be shifting his Iraq policy toward the political center. But Mr. Obama maintains his basic goal of ending the American combat role soon remains unchanged and that he’s always said the American withdrawal must be done carefully.

Mr. Obama also arranged to visit Jordan, Israel, Germany, France, and England, traveling aboard a jet chartered by his presidential campaign, before his return to America. The weeklong trip marks his only foreign excursion as a presidential candidate; Mr. McCain has visited Canada, Colombia, and Mexico, in part to highlight Mr. Obama’s opposition to trade deals with those allies.

Few citizens in impoverished Afghanistan were aware of Mr. Obama’s unannounced visit, and few have been following the American presidential race, being too busy eking out an existence amid soaring violence and with limited access to news media.

But some interviewed today said they would welcome an Obama presidency if he could help their country end the fighting, corruption, and poverty that have crippled it for so long.

“Obama is a good person,” a former army officer, Abdul Basir, 40, said. “During his campaign I heard he was saying that if I become president I will withdraw the U.S. troops from Iraq and bring them to Afghanistan and I will attack on the terror center on other side of border (in Pakistan). It is very important and I appreciated that.”