YANGON, Myanmar — International aid began to trickle into Myanmar yesterday, but the stricken Irrawaddy delta, the nation's rice bowl where 22,000 people perished and twice as many are missing, remained cut off from the world.

In the former capital of Yangon, soldiers from the repressive military regime were out on the streets in large numbers for the first time since Cyclone Nargis hit over the weekend, helping to clear away rubble. Buddhist monks and Catholic nuns wielded axes and long knives to remove ancient, fallen trees that were once the city's pride.

However, coastal areas of the delta worst hit by the high winds and tidal surges were out of reach for aid workers, isolated by flooding and road damage.

Electricity remained cut for nearly all 6.5 million residents of Yangon, while water supply was restored in only a few areas. Some residents waited in lines for nine hours or more to buy gasoline to fuel generators and their cars. At one gas station in the Yangon suburb of Sanchaung, fistfights broke out, with weary residents hitting each other with sticks after someone tried to cut in line.

The U.N.'s World Food Program said international aid began to flow, with 800 tons of food getting through to the first of nearly 1 million people left homeless by the cyclone.

Concerns mounted over the lack of food, water and shelter in the delta region and adjacent Yangon, where nearly a quarter of Myanmar's 57 million people live, as well as the spread of disease in a country with one of the world's worst health systems.

"Our biggest fear is that the aftermath could be more lethal than the storm itself," said Caryl Stern, who heads the U.N. Children's Fund in the United States.

A tidal wave that accompanied the cyclone was more deadly than the winds, Minister for Relief and Resettlement Maung Maung Swe told reporters in Yangon.

"The wave was up to 12 feet high, and it swept away and inundated half the houses in low-lying villages," he said. "They did not have anywhere to flee."

Speaking at a brief ceremony in the Oval Office to honor Aung San Suu Kyi, Myanmar's detained democracy advocate, Bush said: "Our message to the military rulers is, 'Let the U.S. come and help you help the people.'

"We're prepared to help move U.S. Navy assets to help find those who have lost their lives, to help find the missing and to help stabilize the situation," Bush said.

The United States also offered $3 million in emergency aid yesterday, up from $250,000 pledged on Monday. In addition, the Treasury Department loosened restrictions on charity groups to allow them to go into Myanmar without prior U.S. permission.

SOLDIERS FILL STREETS

After days of little military presence in the streets, soldiers were out yesterday clearing massive felled trees with power saws and axes and using their bare hands to lift debris into trucks.

State television played up the effort, showing images of a government truck distributing water, though residents said they hadn't seen any water trucks around the city. There were no images of the hundreds of monks helping the recovery effort.

The streets of Yangon were filled yesterday with residents carrying buckets to bring water from monasteries or buy it from households with generators that could pump it from wells. The main plant of Dagon Ice Factory, a drinking water brand, turned people away, posting signs saying "no more."

While residents of Yangon struggled to clear away the rubble, the Irrawaddy delta was cut off.

Images on state television yesterday showed mangled trees and electricity poles sprawled across roads as well as roofless houses ringed by water in the delta, a lacework of paddy fields and canals where the nation's rice crop is grown.

Based on a satellite map made available by the United Nations, the storm's damage was concentrated over about an 11,600-square-mile area along the Andaman Sea and Gulf of Martaban coastlines — less than 5 percent of the country, but home to nearly a quarter of the country's population.

A C-130 military transport plane carrying government aid from neighboring Thailand flew into Yangon, where an Associated Press reporter watched it unload rice, canned fish, water and dried noodles.

The goods— the first overseas aid to arrive — were transferred to a helicopter, which Myanmar military officers said would ferry them to the most stricken areas.

DEADLY WINDS

Packing winds of about 120 mph, Nargis was the deadliest cyclone to strike in Asia since a 1991 storm killed 143,000 in Bangladesh.

Bryan Whitman, a Pentagon spokesman, said the Navy has three ships in the Gulf of Thailand — the USS Essex, USS Juneau and USS Harper's Ferry — preparing to participate in an annual exercise with Thailand's naval forces.

Pentagon press secretary Geoff Morrell said two aircraft carriers — the USS Kitty Hawk and USS Nimitz — as well as the USS Blue Ridge, are also within reach of Myanmar. The Essex, an amphibious assault ship, has 23 helicopters aboard, including 19 that are capable of lifting cargo, as well as 1,800 Marines.

The Myanmar military, which regularly accuses the United States of trying to subvert the regime, is unlikely to allow a U.S. military presence in its territory.

But reflecting the seriousness of the crisis, the government has appealed for foreign aid and also announced yesterday that it is delaying a crucial constitutional referendum in the hardest-hit areas.

State radio said Saturday's vote on a military-backed draft constitution would be delayed until May 24 in 40 of 45 townships in the Yangon area and seven in the wider delta.

State radio said most of the 22,464 dead, as well as the 41,000 missing, were in the densely populated Irrawaddy delta, home to 6 million people. It said 671 were killed in the Yangon area. Brig. Gen. Kyaw San, the information minister, said most fatalities were caused by tidal waves.

The death toll is the highest from a natural disaster in southeast Asia since the tsunami of December 2004 killed 229,866 people in Indonesia, Thailand and other parts of southeast and south Asia.

The Washington Post contributed to this report.