YANGON, MYANMAR - International aid began to trickle into Myanmar on Tuesday, 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.

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 off for nearly all 6.5 million residents of Yangon; 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 cars. Fights broke out at a gas station in suburban Sanchaung. Weary residents hit 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. Another worry was the spread of disease in a country with one of the world's worst health-care 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.

State highlights troops

After days of little military presence in the streets, soldiers were out Tuesday 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 Tuesday 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 Tuesday 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 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 in the stricken nation -- were transferred to a helicopter, which Myanmar military officers said would ferry them to the most stricken areas.

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 said Tuesday it is delaying a crucial constitutional referendum in the hardest-hit areas.

Vote delayed

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

Pro-democracy advocates, including the political party of detained Nobel laureate Aung San Suu Kyi, have denounced the constitution as a tool to perpetuate the military's grip on power.

Inadequate warnings about the approaching storm and the ineffectiveness of the government in its aftermath could sway angry voters to reject the charter.

State radio said most of the 22,464 dead, as well as the 41,000 missing, were in the densely populated Irriwaddy 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 surges.

Little warning

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.

With 61 dead, Myanmar was largely spared the devastating impact of the tsunami, which killed 130,000 people in Indonesia and 35,000 in Sri Lanka. In its wake, an extensive warning system was established in much of the Pacific region, but Myanmar did not participate. Disaster experts a cited lack of funding and said the country planned to rely on regional systems.

As the cyclone came bearing down late Friday, television broadcasts warned of 120-mph winds and 12-foot storm surges. But electricity is so spotty in Myanmar that few households, especially in the poor rural areas that were worst hit, were aware of the warnings.

The U.N. World Food Program offered a grim assessment of the destruction: as many as 1 million people homeless, some villages almost destroyed and vast rice-growing areas wiped out.