Updated

U.S. Senate Majority Leader Bill Frist said Monday that the Afghan war against Taliban guerrillas can never be won militarily and urged support for efforts to bring "people who call themselves Taliban" and their allies into the government.

The Tennessee Republican said he learned from briefings that Taliban fighters were too numerous and had too much popular support to be defeated on the battlefield.

"You need to bring them into a more transparent type of government," Frist said during a brief visit to a U.S. and Romanian military base in the southern Taliban stronghold of Qalat. "And if that's accomplished, we'll be successful."

Afghanistan is suffering its heaviest insurgent attacks since a U.S.-led military force toppled the Taliban in late 2001 for harboring Al Qaeda leader Usama bin Laden.

According to an Associated Press count, based on reports from U.S., NATO and Afghan officials, at least 2,800 people have been killed nationwide so far this year. The count, which includes militants and civilians, is about 1,300 more than the toll for all of 2005.

The top U.S. military commander in Afghanistan, Lt. Gen. Karl Eikenberry, told Pentagon reporters last month that while the Taliban enemy in Afghanistan is not extremely strong, their numbers and influence have grown in some southern sections of the country.

President Bush has been criticized for his handling of the war and is trying to contain the damage ahead of midterm elections this fall. On Friday, Bush acknowledged setbacks in the training of Afghan police to fight against the Taliban resurgence but predicted eventual victory.

Frist said asking the Taliban to join the government was a decision to be made by Afghan President Hamid Karzai. Karzai's spokesmen were not immediately able to be reached for comment.

Sen. Mel Martinez, a Republican from Florida accompanying Frist on his trip, said negotiating with the Taliban was not "out of the question" but that fighters who refused to join the political process would have to be defeated.

"A political solution is how it's all going to be solved," he said.

Frist said he had hoped the U.S. would be able to withdraw its forces from Afghanistan soon. But he said the 20,000 U.S. troops in the country are still needed to support the NATO alliance, which will assume direct control over most military operations here.

"We're going to need to stay here a long time," Frist said.

The senator said he was warned to expect attacks to increase. There appears to be an "unlimited flow" of Afghans and foreigners "willing to pick up arms and integrate themselves with the Taliban," he said.

He said the only way to win in places like the volatile southern part of the country is to "assimilate people who call themselves Taliban into a larger, more representative government."

"Approaching counterinsurgency by winning hearts and minds will ultimately be the answer," Frist said. "Military versus insurgency one-to-one doesn't sound like it can be won. It sounds to me ... that the Taliban is everywhere."

Frist and Martinez flew to this dust-blown mountain city 220 miles south of Kabul during a one-day stop in Afghanistan on a regional tour that includes stops in Pakistan and Iraq.

The pair had intended to visit a new $6.5 million hospital built by the United Arab Emirates, but a group of wounded Taliban fighters were recuperating there, including a midlevel commander, and U.S. commander Lt. Col. Kevin McGlaughlin canceled the visit because of security concerns.

In violence Monday, a suicide bomber blew himself up next to a NATO convoy in the capital Kabul, wounding three foreign soldiers and three civilians, while a roadside bomb in the eastern Paktia province killed three Afghan soldiers and wounded three others, officials said.

Maj. Luke Knittig, a military spokesman, said he could not disclose the nationalities of the NATO soldiers who were wounded. The attack came two days after another suicide bomber killed 12 people and wounded more than 40 outside Afghanistan's Interior Ministry.

In the southern province of Helmand, five civilians were killed when their vehicle hit a mine on a road usually used by NATO and Afghan forces, said Ghulam Muhiddin, the governor's spokesman.

Suspected Taliban on a motorbike, meanwhile, killed two policemen and wounded two others in Gereshk district, he said. NATO-led troops killed three militants in Nawzad district.