A bomb exploded Tuesday near U.S. and Afghan troops as they patrolled in volatile eastern Afghanistan, killing a U.S. soldier and wounding another, the military said.

The incident occurred a day after suicide bombers rammed cars filled with explosives into NATO peacekeepers in two attacks in the Afghan capital — the first major assault on foreign troops in Kabul in more than a year. The death toll rose to nine Tuesday as police found more bodies in a ditch and a wounded man died.

Police blamed Al Qaeda for the suicide bombings. Such seemingly coordinated attacks are unprecedented in Afghanistan, and reinforced fears that Taliban insurgents are copying tactics used in Iraq.

In the latest violence, the U.S. and Afghan troops were traveling in an armored vehicle in Paktika province when the bomb exploded. Two Afghan soldiers and a civilian were also wounded, the military said.

The death brought to 204 the number of U.S. troops killed in and around Afghanistan since the ouster of the Taliban in late 2001. It comes amid a surge in rebel activity this year that has killed almost 1,500 people.

Monday's bombings occurred within 90 minutes of each other on a 500-yard stretch of road near the headquarters of Afghan-U.N. election organizers. In each case, the attackers rammed their cars into NATO vehicles. Troops thwarted a suspected third bombing by fatally shooting three people in a car racing toward the scene of the blasts.

On Tuesday, officials said police scouring the scene of the second suicide car bombing found six more burned bodies in a ditch and an Afghan man wounded in the blast died of his wounds. Two people had died Monday — a German peacekeeper in the initial blast and an Afghan child in the second.

The blasts underscore the challenges facing U.S.-backed President Hamid Karzai as he struggles to shore up his nation's fledgling democracy. The attacks came two days after officials released results from legislative elections in September, showing a win for Karzai's supporters.

Kabul, home to about 3,000 foreigners and patrolled by thousands of NATO peacekeepers, had been regarded as one of the country's safest places despite a flurry of kidnappings in the past year.

Senior Afghan officials have spoken in recent months of Al Qaeda operatives entering the country to stage assaults, mostly from neighboring Pakistan. In the past two months, there have been eight suicide bombings nationwide, the deadliest in September outside an army training center in Kabul. Previously, such assaults were far less frequent.

A purported Taliban spokesman, Mullah Hanif, claimed responsibility for Monday's attacks and warned of more suicide bombings.

"We will fight with every means to defeat the foreign forces," he said by satellite telephone from an undisclosed location.

Purported Taliban spokesmen often claim responsibility for attacks using information that later proves exaggerated or untrue. Hanif's exact link to the Taliban leadership was not clear.

Germany Defense Minister Peter Struck said the attack showed "there is not a stable, quiet situation in Afghanistan" and that the NATO force is still needed.

"We are dealing with a permanent threat," Struck said in Berlin.

The NATO-led force, known as the International Security Assistance Force, has about 12,000 soldiers from 36 nations in Afghanistan and is responsible for security in Kabul as well as northern and western regions of the country. A separate 20,000-strong U.S.-led coalition is in volatile eastern and southern parts of the country.

While 87 U.S. troops have been killed this year, 24 ISAF soldiers have died, 17 of them Spanish military personnel killed when their helicopter crashed in an accident.