YANGON, Myanmar (AP) -- Myanmar's military regime distributed international aid Saturday but plastered the boxes with the names of top generals in an apparent effort to turn the relief effort for last week's devastating cyclone into a propaganda exercise.

The United Nations sent in two more planes and several trucks loaded with aid, though the junta took over its first two shipments. The government agreed to let a U.S. cargo plane bring in supplies Monday, but foreign disaster experts still were being barred entry.

Despite international appeals to postpone a referendum on a controversial proposed constitution, voting began Saturday in all but the hardest hit parts of the country. With voters going to the polls, state-run television continuously ran images of top generals including junta leader, Senior Gen. Than Shwe, handing out boxes of aid at elaborate ceremonies.

"We have already seen regional commanders putting their names on the side of aid shipments from Asia, saying this was a gift from them and then distributing it in their region," said Mark Farmaner, director of Burma Campaign UK, which campaigns for human rights and democracy in the country.

"It is not going to areas where it is most in need," he said in London.

State media say 23,335 people died and 37,019 are missing from Cyclone Nargis, which submerged entire villages in the Irrawaddy delta. International aid organizations say the death toll could climb to more than 100,000 as conditions worsen.

The U.N. estimated that 1.5 million to 2 million people have been severely affected and has voiced concern about the disposal of bodies.

With phone lines down, roads blocked and electricity networks destroyed, it is nearly impossible to reach isolated areas in the delta, complicated by the lack of experienced international aid workers and equipment.

The junta has refused to grant access to foreign experts, saying it will only accept donations from foreign charities and governments, and then will deliver the aid on its own.

Despite such obstacles, the U.N. refugee agency sent its first aid convoy by land into Myanmar on Saturday and began airlifting a 110 tons of shelter supplies from its warehouse in Dubai, it said.

Two trucks carrying more than 20 tons of tents and plastic sheets for some 10,000 cyclone victims crossed into the country from northwestern Thailand, said the U.N. High Commissioner for Refugees.

"This convoy marks a positive step in an aid effort so far marked by challenges and constraints," said Raymond Hall, UNHCR's Representative in Thailand. "We hope it opens up a possible corridor to allow more international aid to reach the cyclone victims."

A total of 23 international agencies were providing aid to people in the devastated areas, said Elisabeth Byrs, spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs.

Byrs said another U.N. flight with 33 tons of plastic sheets, water and sanitation items and mosquito nets got clearance to take off from Brindisi, Italy later on Saturday.

But a large number of organizations still were awaiting government clearance for more aid shipments, staff and transport.

"It's a race against the clock," Byrs said. "If the humanitarian aid does not get into the country on a larger scale, there's the risk of a second catastrophe," she said, adding that people could die from hunger and diseases.

Health experts have warned there was a great risk of diarrhea and cholera spreading because of the lack of clean drinking water and sanitation.

Farmaner suggested that aid be delivered to the country, also known as Burma, even if the regime does not give its permission.

"We have had a week to convince the regime to behave reasonably, and they are still blocking aid," he said. "So the international community needs to wake up and take bolder steps."

However, aid providers are unlikely to pursue unilateral deliveries like airdrops because of the diplomatic firestorm that it could set off.

So far, relief workers have reached 220,000 cyclone victims, only a small fraction of the number of people affected, the Red Cross said Friday. Three Red Cross aid flights loaded with shelter kits and other emergency supplies landed Friday without incident.

The international Red Cross sent 31 tons of relief goods from Geneva Friday evening, including pumps, generators, water tanks and other water treatment equipment, as well as basic health care for about 10,000 people and surgery material, according to spokesman Marcal Izard.

The shipment was designated for those in labor camps and prisons, he said. He said the agency planned to distribute the aid in coordination with the Myanmar Red Cross, which is the leading relief agency in Myanmar.

The government seized two planeloads of high-energy biscuits - enough to feed 95,000 people - sent by the U.N. World Food Program. Despite the seizure, the WFP was sending three more planes Saturday from Dubai, Cambodia and Italy, even though those could be confiscated, too.

"We are working around the clock with the authorities to ensure the kind of access that we need to ensure it goes to people that need it most," WFP spokesman Marcus Prior said in Bangkok, Thailand.

Richard Horsey, a spokesman for U.N. humanitarian operations, said an international presence is needed in Myanmar to look at the logistics of getting boats, helicopters and trucks into the delta area.

"That's a critical bottleneck that must be overcome at this point," he said in Bangkok.

Heavy rain forecast in the next week was certain to exacerbate the misery. Diplomats and aid groups warned the number of dead could eventually exceed 100,000 because of illnesses and said thousands of children may have been orphaned.

Survivors from one of the worst-affected areas, near the town of Bogalay, were among those fighting hunger, illness and wrenching loneliness.

"All my 28 family members have died," said Thein Myint, a 68-year-old fisherman who wept while describing how the cyclone swept away the rest of his family. "I am the only survivor."

Officials have said only one out of 10 people who are homeless, injured or threatened by disease and hunger have received some kind of aid since the cyclone hit May 3.

The government's abilities are limited. It has only a few dozen helicopters, most of which are small and old. It also has about 15 transport planes, primarily small jets unable to carry hundreds of tons of supplies.

"Not only don't they have the capacity to deliver assistance, they don't have experience," said Farmaner, the British aid worker. "It's already too late for many people. Every day of delays is costing thousands of lives."