The one moment 1st Lt. Ryan Gilchrist will always cherish from his 11 days in Baghdad is when he heard the sound of applause cutting through the darkness on his first night patrol in the devastated city.

Gilchrist and other squad members from India Company of the 1st Marine Division's 3rd Battalion were trying to keep their position a secret, so Gilchrist attempted to hush people who had rushed from their houses to greet them. Misunderstanding his desire, a group of five Iraqis started clapping.

"It was the loudest applause I ever heard in my life," recalled Gilchrist, 25, from Chesterfield, Mo., over the rat-a-tat of a Kalashnikov rifle rippling through the neighborhood. "It was the warmest welcome from people who have been so scared for the last 30 years."

On Saturday, the Marines who now patrol the half of Baghdad east of the Tigris River will begin decamping and heading south. They will not leave Iraq immediately, but will stop in cities along the way to help stabilize them. Within a few days, most of the Marines will be gone from Baghdad and the U.S. Army, which now patrols the western half of the city, will assume full control.

Many Iraqis have protested the U.S. military presence, urging the troops to get out swiftly and leave the nation's rebuilding to Iraqis. Thousands poured into the streets after Friday prayers, chanting for the troops to go home.

The attitude is different in many quiet residential neighborhoods, where the stench of uncollected rubbish fills the air and streets are blocked with concrete and sharp shards of twisted steel to deter looters. U.S. troops say they have been greeted with effusive welcomes by Iraqis who have begged them to stay and keep them safe. People have brought them coffee, tea and hot meals, and joined their patrols to point out caches of weapons hidden in schools, mosques and hospitals. Children cluster around them, and cadge sweets the Marines pull from their prepackaged meals, called MREs.

On India Company's last full day in Baghdad, many of the Marines said they believe they had accomplished something important here, and wished they could stay a little longer to help the city return to normal.

"Before the war, I was iffy about whether we should come to Iraq," said Cpl. Oscar Anguiano, 24, from Fresno, Calif., as he helped pack the armored personnel carrier in which he arrived, with the words El Asesino -- The Killer -- painted on the turret. "I felt, why should we help them? It's their country, not ours. But now I feel we accomplished a lot. It seems our presence makes people feel better, and eventually, they will have a better life."

The 220 men of India Company said they are fortunate that they experienced few casualties in this war. They arrived in Baghdad on April 7, after entering Iraq from Kuwait and passing near Safwan before heading northwest. A staff sergeant lost a leg when he stepped on a mine, and a Navy corpsman running to his aid stepped on another mine, losing both legs below the knees. In Baghdad, one Marine was shot in the arm, apparently when he was mistaken by Iraqi security guards for a looter.

India Company has been assigned a sector of about two square miles just north of the city center. It is a prosperous neighborhood of leafy streets and comfortable middle-class homes. The three-story Marine headquarters once housed an army officers' club. Residents have told them that Iraqi army guards used to shoot at any car that slowed down in front of the building.

Marine squads have branched out to patrol the neighborhoods, stopping for an hour or two to provide security for a bank or a hospital. A pediatrician has often joined them, pointing out the schoolhouses and mosques where weapons were stored.

"There are so many places that need our help," said 1st Lt. Jordan Condo, 27, of Arlington, as he stood outside a branch of the Rafidain Bank, which neighbors said had been looted four or five days earlier. "At many of the banks, looters have come in with ammunition, torches and explosives to break into the safes. The hospitals have been looted. People in the neighborhoods are afraid."

About a dozen Iraqis crowded around the Marines, who were trying to figure how to break into a safe that had been vandalized, hoping to retrieve the money and take it away for safekeeping. Blow it open, some shouted. No, take it away, others countered.

A young man approached, carrying a tray with a dozen cups of tea and coffee in chipped blue cups. Several Marines took cups of dark, rich tea.

"We need them to stay and guard the bank," said Hosnia Alradi Zubaidi, the bank manager, who lives across the street. But not forever, she added. "We appreciate the Marines coming. We thank them for our salvation from Saddam Hussein. But we need them to leave Iraq. This way, it is an occupation."

Inside the bank, where benches were overturned and paint peeled down in sheets from the ceiling, Cpl. Adrian Moraru, 29, of Philadelphia, stood beside a 50-pound flour sack filled with 100-dinar notes, each worth about 2 1/2 cents.

"The whole bag is worth $100, maybe," he said. "They're fighting and killing themselves over worthless money."

Moraru said he remains wary of Iraqis who offer them bottles of water on hot days. He is always on alert; he needs eyes in the back of his head, he said. He had been awakened in the middle of the night by the noise from a firefight just outside the officers' club, lasting about five minutes. And he had just helped remove six rocket-propelled grenades from the garden behind the bank.

"Sometimes, it seems like I survived the war and I could be shot in the back by a 9-year-old," he said. "It was almost easier during the war. At least you knew where your enemy came from. Here, it could be anyone."

Many of the men of India Company said Marines were not intended to be nation-builders.

"Some Iraqis have asked us if we need to kill a family member to get in the Marines," said Gilchrist. "We like the image. If we're passing out MREs and being peacekeepers, we lost the image of the kick-ass Marine."

Capt. Matt Grosz, 31, of Northern Virginia, the commanding officer of India Company, said he hates to leave Baghdad before the task of rebuilding the city is complete. But the most significant task has already been done, Gilchrist said.

"I know some people say we are the arm of imperialism," he said. "But I feel we gave people hope in a world where they never had hope before. This man, Saddam, will never come here to oppress them again."

Spec. Ken O'Toole talks with Iraqi children while on patrol in Baghdad with Kilo Company, 3rd Battalion, 7th Marine Regiment. Community leaders in a Baghdad neighborhood say goodbye after meeting with Marines at their base in a former Iraqi army officers' club.