CAIRO » Witnesses say Sudanese police have opened fire on protesters trying to climb the walls of the U.S. Embassy in Khartoum.

The witnesses say several thousands of Sudanese were protesting outside the embassy, trying to storm it in anger over an obscure file produced in the United States that denigrated the Prophet Muhammad.

It was not immediately clear if any protesters got into the embassy.

The witnesses said at least three protesters were hurt, seen motionless on the ground. There was no immediate confirmation whether they were dead.

The attack came as protests against the film spread around the Middle East and other Muslim countries, from Tunisia to Pakistan.