Updated

NATO warplanes killed at least 11 Taliban fighters in Afghanistan's violence-wracked south hours after militant attacks left one NATO soldier dead and five others wounded, the alliance said Wednesday.

Two roadside bombs also killed three Afghan civilians on Wednesday as renewed bloodshed in the south underscored the persistent threat posed by resurgent Taliban militants to efforts to extend the reach of the U.S.-backed government of Afghan President Hamid Karzai.

Tuesday's NATO airstrikes occurred in the Zhari district of Kandahar province, a former Taliban stronghold, said alliance spokesman Maj. Scott Lundy.

Fifteen militants were preparing an ambush on the main highway in the area but fled into a compound after realizing they were being watched. A subsequent bombing raid killed 11 militants, Lundy said. It was unclear what happened to the other four.

NATO troops also killed one Afghan youth and wounded another following a suicide bombing Tuesday in Kandahar city that targeted a Canadian convoy, killing one soldier and wounding three, the alliance said Wednesday.

CountryWatch: Afghanistan

Troops fearing a follow-up attack after the blast on Tuesday fired a single bullet at the two youths as they approached on motorbike the scene of the bombing, a NATO statement said.

A purported Taliban spokesman claimed responsibility for the bombing, which also killed one child.

Two Canadian soldiers were also wounded Tuesday in a separate attack in the south.

On Wednesday, two roadside bombs struck a truck and a motorbike in the Kandahar district of Daman, killing three civilians and wounding one, said Dawood Ahmadi, the provincial governor's spokesman.

Ahmadi blamed Taliban militants for the bombs, which were planted on a road usually used by NATO and Afghan forces. It was unclear if any soldiers were in the area at the time of the blasts.

More than 1,000 people, mostly militants, have died in the last three months. Thousands of NATO and Afghan forces are battling Taliban fighters, believed backed by armed opium dealers, in southern provinces to extend the reach of Karzai's government.

It's the country's worst spate of violence since the Taliban regime's 2001 toppling by American-led forces for hosting Osama bin Laden.

Karzai's office announced Wednesday that the president will travel to Washington "in the near future" following an invitation from U.S. President George W. Bush.

Bush telephoned Karzai on Tuesday to extend the offer and pledge continued American support to the war-wracked country, Karzai's office said in a statement.

"Both presidents talked about the situation in Afghanistan and the region," the statement said. "They discussed the progress Afghanistan, with the help from the United States, is making in fighting terrorism and rebuilding Afghanistan."

Karzai last visited Bush in Washington in May 2005, when the two leaders signed a strategic partnership agreement that ensures long-term U.S. support for Afghanistan in economic, security and other sectors. Bush also made a surprise visit to Kabul in March.