The day the Iraq war began, Abid Hassan Hamoodi, 72, patriarch of one of Basra's most prominent families, gathered everyone into the storeroom of the nine-bedroom family home. Because it was away from the street, he thought, that room was the safest place in the house for the children and grandchildren to sleep.

The room turned out to be a death trap.

In the early morning hours Saturday, while they slept, 10 members of his family were killed by two missiles fired from a warplane that destroyed the house, Hamoodi said. The victims, including seven children, were crushed when the back room of the house became a pile of cement rubble. Hamoodi said he lost his wife, a daughter, a son and seven grandchildren. He dug out three other family members with his bare hands, he recalled today, after hearing cries of "Baba! Baba!" -- "Father! Father!" -- from under the collapsed brick.

Hamoodi, a retired safety manager for South Oil Co., is not a political man. His children are professionals -- mostly doctors, with some engineers -- and he has three sons living in Britain. As head of a respected Shiite Muslim family, he might have been expected to welcome the U.S.-British invasion of Iraq to end the three-decade rule of President Saddam Hussein. But, instead, he is angry.

"What was the purpose of the American invasion of Iraq?" he asked during a Muslim ceremony marking three days of mourning for the dead. "Was it to topple Saddam Hussein, or to kill innocent people?

"Why did this happen?" he asked. "Ten lives are gone. The house was completely destroyed. . . . You came to save us, to protect us. That's what you said. It's now the contrary. Innocent people are killed."

The extent of Hamoodi's loss may be unusual, his rage fueled by grief. But the sentiment he expresses -- that the U.S.-British occupation has produced more harm than good -- is widely voiced here in Basra.

Allied war planners had predicted that Basra, Iraq's second-largest city with 1.3 million inhabitants, would welcome U.S. and British troops. The Shiite majority here rebelled against Hussein's government after the Persian Gulf War in 1991, and hundreds, if not thousands, were killed when the government crushed the revolt and the United States failed to intercede.

Many residents have indeed expressed relief that the Baath Party apparatus, led by Sunni Muslims, is gone. And many have voiced their anger at the abuses committed in Hussein's name over the years.

But alongside the demonstrations of joy lies ambivalence -- even hostility -- toward the British military presence. Mostly, this is the result of a 21/2-week siege of the city that many residents say produced unnecessary civilian casualties. The Hamoodi family's tragedy is one example. But there are others, visible in hospital emergency wards where women and children lie suffering from burns and amputated limbs.

And now, two days after British troops advanced into the city, finding little resistance, many more residents are complaining about their behavior. Some people say their relatives have been taken away for questioning by British troops who suspect them of being pro-government militia members.

Hamdia Khudain is looking for her sons, Falah Hassan, 27, and Salah Hassan, 22. They stayed in the family home, next to a Baath Party branch office, while other family members went elsewhere for safety. But when she returned, her sons were missing. Neighbors said they were taken away by British troops, who knocked down a wall that separated her home from the Baath complex.

"I want my sons -- just tell me where they are!" she beseeched a reporter. "It is the responsibility of the British army. They came in order to set us free from Saddam, not to take our children."

Others complain that the British soldiers have entered their houses for searches, kicking in doors and upending furniture, because they live near Baath or militia facilities. Safaa Ju, 33, a Christian Iraqi businessman, showed reporters where British soldiers kicked in a bedroom door and ransacked another room in his home, because, he speculated, a senior intelligence officer had a house in the same middle-class neighborhood.

By far the most common complaint -- voiced here repeatedly to any foreigner who stops a car and attracts a crowd -- is that Basra has descended into anarchy and British forces have done little to establish security.

The looting frenzy has touched nearly everything. Government offices, banks, shops, hotels and homes have been stripped bare. Carjackings have begun as well. Tahrir Hospital, in the port area, reported one of its vehicles was taken at gunpoint this morning, a few hundred yards from the main gate. Another hospital reportedly had an ambulance stolen. Looters were later seen using the ambulance to load looted furniture from another house.

"Now that the British have military control, there's no law and order," said Andres Kruesi, the delegate here of the International Committee of the Red Cross. "People steal everything. They even steal fire trucks."

"We felt safe when Saddam Hussein was controlling the situation," said Ammar Mohammed, 32, who works as a security guard for a hotel. "Now, this safety, this security, is absent."

"We need security. There is no security in the city," said Archbishop Gabriel Kassab, 64, leader of southern Iraq's small Catholic Chaldean community. "I think that is the responsibility of the Americans and British. Before they came, the city was very quiet. . . . Then there was trouble."

British military commanders agree that looting and disorder is a problem, but they say they are not here as a police force. British military officials announced today that a local sheik, whom they did not name, has been chosen to set up a city administration. But in the meantime, the power vacuum continues.

Col. Chris Vernon, a spokesman for the British military, told the Agence France-Presse news agency there was no humanitarian crisis in Basra, which has enough food to last until the end of May. But he said the British forces would try to increase supplies of drinking water.

Today, British officers placed troops at places considered key installations, such as hospitals and some public utilities, to prevent looting. But there are too few troops to protect the entire city from freely roaming mobs.

Until a government and police force can be formed, however, the British troops provide the only security in town, and as a result they are facing the rising anger of residents.

"With the British soldiers, it is free now -- free to take anything you want," said Hayder Toma, 31, an employee of the state electrical company, who is afraid the city's electrical system will collapse because thieves are taking the machinery.

"The occupying power has an obligation to keep things running," said the Red Cross's Kruesi. "They're not a police force, but they're an occupying power, so they have to establish a police force."

A girl who is eager to receive her water allotment tries to sneak past a British soldier at a distribution center in central Basra. Iraq's second-largest city has enough food, but water is becoming scarce.British soldiers control a cheering crowd as they reclaim foodstuffs that had been looted earlier in the day in Basra. British forces have asked a local sheik to set up a city administration.Iraqis rest on a sofa looted from the bombed-out remains of city hall the day after British forces took control of Basra.Children scramble onto a truck carrying looted food. British troops stopped the truck and doled out the food.