Polish soldiers opened fire on a bus full of Shiite Muslim (search) pilgrims from Iran after it failed to stop at a checkpoint Sunday, witnesses said. Ten people were hurt, including eight Iranian pilgrims, a Polish soldier and member of the Iraqi security forces, they said.

Polish officials, however, denied that the bus was carrying anyone but the driver and said they suspect the incident was an aborted terrorist attack.

The bus, apparently having brake troubles, struck a minivan and swerved into a concrete barrier at a checkpoint manned by Polish and Iraqi security forces, witnesses said.

Abbas Hassan, a member of the U.S.-trained Iraqi Civil Defense Corps (search), said Polish troops opened up with heavy firepower for several minutes, targeting all cars coming in on the highway from Baghdad. He said the gunfire destroyed the right side of the bus.

Another witness, who was in another car at the checkpoint, said the bus appeared to be having brake troubles when it hit the barrier. He said the bus had a capacity of 44 passengers and was full.

The witness saw bleeding passengers pulled from the bus, as well as from another vehicle behind it carrying more than a dozen people. Hassan said one Civil Defense Corps officer lost his leg when a piece of the bus struck him.

The director of the hospital in Karbala (search) refused to let reporters inside, saying none of the wounded had been taken there. But a police officer and a medic who had gone to the scene said eight Iranians were being treated for slight injuries, as well as the officer who lost his leg.

Polish Col. Zdzislaw Gnatowski, a military spokesman in Warsaw, Poland, said one Polish soldier was evacuated to a hospital in Karbala, 12 miles south of the checkpoint.

The commander of Polish forces in Iraq, Gen. Mieczyslaw Bieniek, denied that Polish troops fired on pilgrims and insisted the bus was empty except for the driver, whom the general described as "a lone terrorist who might have had explosive materials."

Bieniek said troops were searching for explosives.

Shiite Muslims are traveling to the holy city of Karbala, 50 miles south of Baghdad, for the 10-day festival of Ashoura, which is expected to draw 1.5 million pilgrims, including about 100,000 Iranian Shiites.

The festival marks the death of one of the Shiites' chief saints, Imam Hussein, a grandson of the prophet Muhammad.

Further south, hundreds of Iraqis rallied against coalition troops Sunday after U.S. soldiers fired on a car that failed to stop when a military convoy passed by. One Iraqi was killed and another critically wounded.

The shooting took place near Rumaythah, 135 miles south of Baghdad near the city of Samawah, where Dutch soldiers and some 230 Japanese troops are based. The soldiers are working to supply Iraqis with clean water, rebuild schools and bolster local hospitals.

Despite not being involved in the violence, the rally caused Japanese commander Col. Koichiro Bansho to cancel his trip to the town.

A crowd gathered around the site of the shooting, where the car sat with its windows broken, chanting "Down with America! Down with Bush!" U.S. soldiers and Dutch marines trying to clear the roadway were pelted with rocks and taunted.

"If these massacres don't stop, we shall fight the Americans!" one unidentified protester yelled. "Why do we have to be nice, to cooperate with them? Why do they do this to us?"

An Associated Press Television News reporter said the crowd's anger was focused on the American soldiers and that Dutch marines ultimately calmed the crowd.