ARBALA, Iraq, Dec. 28 — So revered is this city among Shiite Muslims around the world that its golden domes and minarets draw millions of pilgrims each year to spiritual reflection.
But a day after four suicide car bombs killed seven coalition soldiers and seven Iraqi policemen and injured more than 100 others, Karbala is a city transformed, joining the ranks of other wounded places in Iraq where security can no longer be taken for granted. Here, in what were once relatively peaceful streets, the rumble of Humvees and the loading of Kalashnikovs are sounds that are becoming as familiar as the calls to prayer.
Iraqi policemen stand watch in 24-hour shifts at government buildings and carry AK-47's when attending the funerals of their colleagues. The Polish military has imposed a curfew from 9 p.m. to 6 a.m. Bulgarian soldiers have set up roadblocks and checkpoints around the city.
Though the rise in military activity makes some residents here feel more secure, it also increases the resentment of others toward the occupying forces. That psychological damage is in addition to the deaths and injuries caused by exploding bombs. The stepping up of security is especially noticeable here in the south, which has been the site of far fewer attacks against the American-led forces than places north of Baghdad.
"If people want to live peacefully and simply and with stability, this attack makes them nervous," Afdal al-Shami, a representative of the shrine of Hussein, said as hundreds of Shiite worshipers milled around the inner courtyard of the blue-tiled building. "And the people in Karbala don't like the military around. We don't want to see more soldiers."
About 500 Polish and 500 Bulgarian soldiers are stationed here, with smaller contingents from other countries. Nervous, seething with anger, they were out on the streets in force on Sunday. Four Bulgarian and two Thai soldiers died in the attacks the previous day and a fifth Bulgarian soldier died from his wounds today. The Polish military, which controls this region, decided to increase street patrols and set up more checkpoints, said Capt. Irek Jankowski, an army spokesman.
The assaults in Karbala were the deadliest in a string of ambitious and bloody strikes this holiday week. More came today, when an American soldier and two Iraqi children were killed and five American soldiers wounded in central Baghdad by a bomb that exploded at 10:13 a.m. Three hours later, another soldier was killed and three wounded when a bomb exploded by their convoy in the town of Falluja.
At one checkpoint in Karbala, a Bulgarian sergeant was yelling in broken English at two Iraqi men whose blue Corsica was parked by the median with the hood up. The two Iraqis shouted back at him in Arabic, frantically gesturing with their hands to the car's engine.
The sergeant turned to an Iraqi interpreter who had accompanied a visitor to the scene.
"Tell him he can't go anywhere unless he opens the trunk," the sergeant said.
The driver, Karim Muhammad, shouted back: "The battery of my car is dead. I absolutely can't open the trunk."
The sergeant glared at the men and walked way. The men began fiddling with the battery. After a few minutes, the sergeant returned.
"What's he doing?" the sergeant yelled. "Tell him to do it quicker. And tell him to be quiet."
Mr. Muhammad said, "We don't have the tools for the battery."
Pointing to the side of the road, the sergeant said, "Look, I want this car over there, O.K.? Over there. Right now."
Mr. Muhammad and his friend slowly pushed the car to the side of the road. Asked whether he and his colleagues were scared, the sergeant answered: "Scared? We're scared? We're mad."
Mr. Muhammad and his friend stared at the Bulgarian soldiers, who had blocked the road with two jeeps. A group of a dozen men and boys gathered around Mr. Muhammad. The soldiers stared back, hands gripping AK-47's.
"We like the checkpoints," Mr. Muhammad said. "It'll impose security. But it was disrespectful the way the soldier talked to us. The way they treat us is very bad. The Bulgarians and the Polish here are terrible. At least we can understand the Americans a little bit. It's going to be hard for us, and we're going to face more miseries as long as the occupation is here."
The rise in tension in Karbala is inevitable, given the devastating nature of the attacks on Saturday afternoon. Using car bombs and various projectiles, insurgents simultaneously struck at three sites in a straight line across the city, from the northwest to the southeast.
The fighters targeted a Bulgarian base in the north; a compound containing city hall and police headquarters in the center; and a multinational logistics base staffed by Polish, Thai and American soldiers in the south. Insurgents used two suicide car bombs in that last attack, and one each in the others.
Today, people were still trying to deal with the aftermath. The chief of police, Abbas Fadil, walked past dozens of his officers into a funeral home and solemnly shook the hands of several clerics. Down the block, worshippers from across the Middle East and Central Asia marched around the city's gleaming shrines. Two Humvees rolled through the nearby bazaar at dusk, drawing stares from pilgrims as the last echoes of the call to prayer faded.