ANGOL, Chile — Chile’s government, after initially waving off outside aid, changed course Monday as the devastation from the powerful earthquake sank in and the nation’s pressing needs became clear.

With the desperation of many Chileans mounting, the United Nations said that the government had asked for generators, water filtration equipment and field hospitals, as well as experts to assess just how much damage was caused by Saturday’s magnitude 8.8 quake, one of the largest ever measured.

“Everything is now moving,” said Elisabeth Byrs, a spokeswoman for the United Nations Office for the Coordination of Humanitarian Affairs. “We are looking immediately to match the needs.”

Chile has always been considered Latin America’s most earthquake-ready country. Its children learn to run for cover during quake drills before learning to read. Its building codes are robust. Its disaster manual is thick, laying out all the scenarios for the temblors that are a regular part of life.

But despite all that, the powerful quake that jolted Chileans awake has left the country reeling. Collapsed bridges and damaged roadways have made it difficult to even get to some areas. Downed phone lines and cellular towers have made it impossible to communicate. And many residents in the most damaged areas have not only taken food from supermarkets, but also robbed banks, set fires and engaged in other forms of lawlessness.

“The looters are more organized,” said the mayor of Concepción, Jacqueline Van Rysselberghe, asking for more troops, Reuters reported.

The quake has also exposed the fact, experts say, that although Chile is one of the most developed countries in the region, it is also one of the most unequal, with huge pockets of urban and rural poor, who suffered most in the quake.

“It’s the poorest Chileans who live near the epicenter,” said Carolina Bank, a Chilean-born sociology professor at Brooklyn College.

It was not just the violent shaking that tore Chile apart, but also the surge of waves that swept in along the coast, damaging homes like that of Edmundo Muñoz, 44, and his family, in Constitución. “Everything was destroyed,” he said.

A growing perception has begun to set in among many residents that the country was not as well prepared as it had thought.

In Santiago, the capital, those left homeless after their brand-new and supposedly earthquake-resistant apartments suffered severe structural damage were furious. Chileans are wondering aloud why food is not getting to the hungry faster and why the politicians and soldiers seem to have been caught flatfooted.

“The government has been very slow to respond,” complained Victor Pérez, 48, who was sleeping in a tent with his girlfriend outside their ruined Santiago apartment building. “We have no water or lights, and most of the stores nearby are out of food.”

The frustration could be heard on Chilean radio, where residents called in to complain that government provisions had been slow to arrive and that almost all markets and stores had been stripped bare of food, water and other supplies.

Here in Angol, an inland town where the streets were strewn with the rubble of collapsed businesses, some basic services were beginning to come back on line, if only slowly.

Electricity was being restored in patches, though many streets and windows remained dark. The main hospital, built to withstand earthquakes, had been rendered unusable, and the closest alternative was almost 90 miles away. Gasoline had started pumping again, and at least 40 cars lined up at a local station. Thirty more people waited on foot in a tense line for gas, holding empty plastic bottles normally used for milk or water. Scuffles broke out, and nerves were frayed.

“Everyone’s on edge,” Ana Bizama, 42, said as she stood in line. The threat of aftershocks was on everyone’s mind.

The government, which declared a state of emergency Sunday and deployed the military to the hardest-hit areas, said it never dismissed outside assistance but wanted to see how bad things were first.

“Experience over the years and in prior earthquakes, as well as from international cooperation efforts like in Haiti, have left us lessons,” Foreign Minister Mariano Fernández told reporters. “We have to be very precise about what our needs are in order for the assistance to be of any use.”

As each day passes, it becomes clearer in Chile that those needs are huge.

While the effects of the earthquake appear worst in outlying areas, the capital itself received a significant jolt, as Mirko Boskovic, 43, a postal worker, could attest. “It looks like the Tower of Pisa,” Mr. Boskovic said, gazing at his teetering apartment building, supposedly seismically secure, which leaned precariously at a 45-degree angle and was ringed by police tape.

The numbers of damaged buildings is increasing, not just from aftershocks but from troublemakers who have set fire to businesses in the damage zone, including one building in Concepción that collapsed on Monday.

President Michelle Bachelet has just 10 days left in office, leaving her successor, Sebastián Piñera, little time to get up to speed on governing. One official in the current administration, who did not have authorization to speak on the record, suggested that the looming transition was already complicating the response.

Residents also feared that the transition would make the aid effort bumpy. “Soon, people are going to start organizing and demanding that they fulfill the many promises they have made on television and the radio,” said Jesse Salazar, 49, who watched over his sister-in-law’s belongings as she packed up boxes to move from her damaged home.

Secretary of State Hillary Rodham Clinton, beginning a tour of Latin America on Monday, told reporters that the Bachelet government had asked the United States for dozens of satellite phones to help overcome the damaged telephone networks and that she would bring some when she stopped in Santiago on Tuesday for a previously scheduled visit. More American aid would probably follow as Chilean officials better survey the damage, Mrs. Clinton said.

The United States had search-and-rescue teams at the ready Monday, and Washington had also offered the Chileans a list of other emergency supplies it could provide if requested. Already, American officials passed to the Chileans satellite imagery so they could better assess the damage in outlying areas.

Just weeks ago, it was Chile that was giving aid, not getting it.

Chilean rescue personnel, soldiers and aid workers played a significant role in Haiti. In fact, some officials said that had left the government short of the plastic sheeting and tents it needed for the nearly 2 million Chileans displaced or otherwise affected by the quake this week.

Still, Chile’s earthquake preparedness clearly saved lives. Laura Torres, 62, and her husband, Víctor Campos, 66, live in Constitución, a city flanked by the ocean and a river. When they quake struck, the earth shook so violently they could not stand.

They crawled to assist their son, who is severely brain damaged; Mr. Campos picked him up, trying to walk as the earth heaved. They ran up into the hills, amid wails from others around.

In the tsunami-prone region, earthquake training had taught them that they had about 20 minutes to make it to high ground, Ms. Torres said, but the roaring of the water, a strange sound like a plane’s motor, suggested that it was barreling in much sooner.

Still, they made it to the hills and are now staying with one of their daughters and about 30 other people, rationing what little food they have. Other survivors are camping in the hills, making fires and sharing food. Naked or partially naked people have streamed by the house, Ms. Torres said, asking for clothes.

Some homes not far from hers have vanished. The water left fishing boats in the plaza, Ms. Torres said, carrying away train cars and replacing businesses with “mud, debris, destruction.”

“It’s a ghost town,” she said.