KERBALA, Iraq Police ordered hundreds of thousands of pilgrims to leave the Iraqi city of Kerbala on Tuesday after fierce clashes between security forces and gunmen killed 52 people during a major Shi'ite religious festival.
Interior Ministry spokesman Brigadier-General Abdul Kareem Khalaf told state television that reinforcements had been rushed to Kerbala from Baghdad and neighboring provinces.
Late into the night, the area near two of Shi'ite Islam's holiest shrines came under heavy fire, a senior Shi'ite official in charge of the holy sites in the city said.
Asked if the gunfire was targeting the revered Imam Hussein and Imam Abbas shrines, the official said: "Yes." He urged the government to immediately bring the situation under control.
A senior security source in Baghdad said 52 people had been killed and 206 wounded in the day-long clashes.
The fighting earlier in the day appeared to be between gunmen loyal to the fiery Shi'ite cleric Moqtada al-Sadr, possibly members of his Mehdi Army militia, and police linked to the rival Shi'ite political movement, the Supreme Iraqi Islamic Council (SIIC), and its Badr Organisation.
In a sign the violence was spreading, police said five people had been killed hours later in fighting between Mehdi Army militia and supporters of the Badr Organisation in Baghdad. Police said gunmen attacked five SIIC offices in the capital.
Sadr, one of Iraq's most influential clerics, urged calm.
"Moqtada al-Sadr demands calm and asks the Sadrist followers not to take part in the disturbances," Hazem al-Araji, a senior aide to the cleric, told Reuters.
Police said a curfew had been imposed in Kerbala and pilgrims ordered to leave the city, 110 km (70 miles) south of Baghdad, bringing to an abrupt halt a major Shi'ite festival that was to have run for two days until Wednesday.
Pilgrims had been marking the 9th-century birth of Mohammad al-Mahdi, the last of 12 imams Shi'ites revere as saints.
"They came in big buses and now police are forcing them to return on these buses," said one local police official.
Iraq's security forces had originally feared that Sunni Islamist al Qaeda might try to launch a large-scale attack on the pilgrims to inflame sectarian tensions.
Police said gunmen armed with automatic weapons and pistols had earlier tried to take over the area around the two shrines, the focal point of Tuesday's ceremonies. Thick smoke from burning cars billowed over the city.
STRUGGLE FOR DOMINANCE
Sadr aide Araji said the clashes erupted when police objected to pilgrims chanting pro-Sadr slogans and began beating them.
The Sadrists and SIIC, the two biggest Shi'ite blocs in parliament, are locked in a power struggle for control of towns and cities in Iraq's predominantly Shi'ite south. The police in many of these towns are seen as loyal to Badr.
Analysts fear the struggle for dominance will intensify ahead of provincial elections expected to take place next year.
The fighting is likely to be seen as embarrassing for Prime Minister Nuri al-Maliki, who wants to show that his security forces can take control of security from U.S.-led forces.
One of his two deputies, Barham Salih, warned in an interview with Reuters late on Monday against an early U.S. troop pullout.
"A premature withdrawal of troops from Iraq will be a disaster," Salih said.
"It will lead to an all-out civil war, it will lead to a regional war in my opinion because the fate of Iraq is crucial to the regional balance and to regional security."
U.S. jets were dispatched to fly over Kerbala as a "show of force" at the request of Iraqi authorities, but that was the only U.S. participation so far in the operation, said Major Alayne Conway, spokeswoman for U.S. forces south of Baghdad.
Tuesday's violence followed clashes late at night between police and pilgrims in the city in which the local hospital said seven pilgrims were killed and 35 wounded.
(Additional reporting by Dean Yates, Wisam Mohammed, Aseel Kami, Ahmed Rasheed, Mariam Karouny, Waleed Ibrahim, Peter Graff in Baghdad)