Fighting between U.S. forces and suspected Taliban rebels on Tuesday killed one American service member and wounded two others in southern Afghanistan, the military said.

A military vehicle was damaged by a roadside bomb during the fighting, which left the two wounded service members in stable condition at a nearby base.

"We are deeply saddened by the loss of one of our fellow service members," said Maj. Gen. Benjamin C. Freakley, a U.S. commander.

The victims' names were withheld pending notification of their families.

The bombing raised the death toll of U.S. personnel in and around Afghanistan to 216 since the U.S. invaded in late 2001.

Military officials in Washington and Afghanistan said Tuesday that insurgent attacks rose sharply last year and are likely to worsen in 2006 as militants step up efforts to hamper the country's gradual transition to democracy.

Army Col. Kevin Owens told a ceremony to mark the handover of command for southern Afghanistan to Canada that insurgents have carried out increasingly desperate attacks because Afghanistan's growing democracy has reduced their ability to "terrorize and dominate" the population.

"There will be an increase in violence this spring and we forecast an increase of violence in summer," Owens said. "Afghanistan is building state institutions, is building a civil society — that's why the enemy is resorting to the tactics that he's resorting to."

In Washington, the head of the Defense Intelligence Agency told Congress on Tuesday that violence in Afghanistan increased 20 percent in 2005.

"We judge insurgents now represent a greater threat to the expansion of Afghan government authority than at any point since late 2001, and will be active this spring," Lt. Gen. Michael Maples said.

There has been a spate of about 25 previously rare suicide bombings in the past four months.

Owens said the change in tactics was intended to "attack the will and confidence" of Afghans and the international community.

In his written testimony to the Senate Armed Services Committee, Maples said Afghan insurgents had increased their suicide attacks almost fourfold and more than doubled their use of improvised explosive devices. Both techniques have been used frequently in Iraq.

Seven militants were captured during the deadly battle Tuesday in Uruzgan province, a military statement said.

The United States has about 18,000 troops here and plans to withdraw between 2,000 to 3,000 of them later this year.

Canada has sent some 2,200 troops to the region to replace some U.S. forces.

About 3,000 British forces are arriving and 1,200 Dutch soldiers are expected later this year.

Some 1,600 people were killed last year, the most since U.S.-led forces ousted the Taliban in 2001. The development has raised fears for this country's slow transition to democracy after a quarter century of war.