Spanish-led troops and Iraqi police fought a three-hour gun battle with Iraqi Shi'ite militiamen near Najaf today, leaving at least 20 people dead and some 200 wounded, witnesses and medical officials said.
The shooting began after protesting militiamen marched on a Spanish-run military base in Kufa, near Najaf, to denounce the arrest of an aide to a radical Shi'ite cleric and last week's closure by US authorities of a militant Baghdad newspaper.
In a statement from Madrid, Spain's Defence Ministry said four soldiers from El Salvador were killed in the fighting and nine wounded. Salvadoran and other soldiers from Spanish-speaking countries are headquartered in Najaf. The statement said Spanish troops also fought in the clashes.
Dr Falah al-Numhna, the director general for health in Najaf, told Reuters news agency 20 people were killed and at least 200 were wounded in the firefight. He said he believed at least two Iraqi police were among the dead. A Reuters correspondent who saw many of the dead said most were wearing the black uniform of the Mehdi Army.
Witnesses said the demonstrators, many of them armed, threw stones at a military vehicle arriving at the base and shortly afterwards Spanish-led troops and Iraqi police at the base opened fire on the crowd from several directions.
Black-clad members of the Mehdi Army, a banned militia loyal to radical anti-American cleric Moqtada al-Sadr returned fire at the heavily defended garrison. Fighting continued for around three hours before dying down.
In Baghdad, a spokesman for Sadr said the cleric had called for an end to protests, asking his supporters instead to gather at his offices or in mosques.
"He has put out a statement calling to stop the protests, because they will get you nowhere," Mr Abd al-Hadi al-Daraji said. "These arrogant powers say thank you for your peaceful protests and then fire on the demonstrators."
Most of the fighting took place between the garrison, at the side of a road leading out of Najaf, and an industrial area of mechanics' workshops and junkyards across the street.
Witnesses said militiamen, some appearing as young as 17 or 18, would occasionally emerge from the area and unleash rounds from assault rifles before running for cover again.
"I was standing next to the tree and then I felt fire in my leg and I fell to the ground," said Hamza Mussewi, an unarmed protester who was shot in the knee.
In linked clashes in central Baghdad, Iraqi security forces opened fire on a Shi'ite protest today and in the northern city of Kirkuk a suicide car bomber exploded his vehicle, wounding two US soldiers and five Iraqis, police said.
Sadr's supporters have staged several marches in the past week to protest against the closure a week ago of al-Hawza newspaper, a mouthpiece for Sadr that US-led authorities in Iraq accused of inciting anti-American violence.
In recent days, they have also angrily protested against the arrest of Mustapha Yacoubi, an aide to 30-year-old Sadr, who they say was seized in Najaf on Friday by members of the US-led coalition of forces occupying Iraq.
Spanish troops deny detaining Yacoubi, but said today other coalition members may have arrested him.
Separately, the US military said two US Marines were killed in attacks over the weekend in a volatile province west of Baghdad where earlier this week four US contractors were killed, burnt and dragged through the streets by a jubilant mob.
The deaths raise to 411 the number of US troops killed in action in the year since US-led forces invaded to overthrow Saddam Hussein.