Kabul, Afghanistan - – Hopes and fears among Afghans clashed during the weekend visit of presumptive US Democratic presidential nominee Sen. Barack Obama, who has vowed to send more US troops to Afghanistan if elected.

Among those familiar here with Senator Obama, his trip revived debate about America's military presence in their country. The US has the most soldiers in Afghanistan and donates the most money. Obama has proposed adding two more brigades, or about 7,000 troops.

"We have to understand that the situation is precarious and urgent ... and I believe this has to be the central focus, the central front, in the battle against terrorism," Obama told the CBS television program "Face the Nation" Sunday. "I think the situation is getting urgent enough that we have to start doing something now."

Mustafa Rawan, a young professional who says he was aware Obama had been in town, showed enthusiasm for the candidate and the presidential election. "I hope and feel he will be the winner in the presidential elections," he said.

Mr. Rawan said he supported the presence of the US troops in Afghanistan but that US help should go beyond rhetoric. "If they really want to help, they can make a difference. If they just want to say it rather than doing anything, it will be difficult."

Another young man, Latif, was less optimistic. A change in the White House would not have any impact on the US policy in Afghanistan, he said. "I think the US has a double face. They say they want to defeat the Taliban, but they are not."

Obama's trip to Afghanistan was part of a congressional delegation including senators Chuck Hagel (R, Neb.) and Jack Reed (D, R.I.) that will continue on to the Middle East and Europe.

Saturday began with visits to the Bagram Air Field north of Kabul to meet military leaders and soldiers, then to Jalalabad Air Field, where Obama was briefed by Nangarhar provincial governor Gul Aga Sherzai. "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," Mr. Sherzai told The Associated Press.

After breakfast with troops on Sunday, Obama met with Afghan President Hamid Karzai, whom the senator criticized this month for having "not gotten out of the bunker" to help organize the country.

Presidential spokesman Humayun Hamidzada said that during their lunch, where they discussed issues "at the broad level," Obama "conveyed his commitment to ... supporting Afghanistan and to continue the war against terrorism with vigor."

The senator's visit coincided with civilian casualties caused by foreign forces, a recurring problem that hurts popular support for them and for the government. NATO said Sunday that its troops accidentally killed at least four civilians in the eastern Paktika province. In the western Farah Province, coalition forces killed up to nine Afghan police.

• Wire material was used for this report.