A C-130 military transport plane left Thailand's Vietnam War-era U-Tapao airbase carrying 12,700 kg of water, mosquito nets and blankets. U.S. aid officials said they hope it will the first of many U.S. flights to the army-ruled former Burma.

Greeting the plane at Yangon airport was the junta's Navy Commander-in-Chief Soe Thein, who promised to deliver the supplies "as soon as possible" to the cyclone-hit region, a U.S. embassy official in Yangon said.

"This is Burma's hour of need and the need is urgent," U.S. Agency for International Development administrator Henrietta Fore said before boarding the plane with a Thai-U.S. delegation for the short flight to the cyclone-hit city of Yangon.

Admiral Timothy Keating, head of the U.S. Pacific Command, had said before taking off that he would urge the junta to allow a "long, continuous train of flights" that could carry up to 200,000 pounds of relief goods a day.

"We're limited only by the permission from the authorities in Burma," Keating said at the Thai air base.

MINIMAL AID DELIVERIES

The World Food Programme is delivering emergency food to Myanmar's cyclone-ravaged Irrawaddy delta at just a fraction of the rate needed by the storm's 1.5 million survivors, officials said on Monday.

"We think we need to be moving 375 tonnes of food a day down into the affected areas. We are doing less than 20 percent of that," WFP spokesman Marcus Prior said in the Thai capital.

Medecins Sans Frontieres said three cargo planes from Europe carrying medical material and other supplies were scheduled to arrive in Myanmar on Monday.

"More than one week after the disaster, despite the sending of three cargo planes and some positive signals, it has been very difficult to provide highly needed supplies for the heavily affected population in Myanmar," MSF said in a statement.

"In the areas where we have been, we haven't seen any aid being delivered so far, so the amount that has reached people in the areas where we are had been minimal," MSF said

MSF already had a big presence in Myanmar before the cyclone. Aid agencies that did not are having even greater difficulties.

While Myanmar's reclusive military government is accepting aid from the outside world, including the United Nations, it will not let in foreign logistics teams, who were queuing up in Bangkok hoping to get visas from the Myanmar embassy.

The U.N. said its top representative in Myanmar had flown to Naypyidaw, the generals' new capital, on Monday to hand over in person a list of 60 "critical" U.N. and relief agency staff.

Despite this, U.N. officials said none of its staff in Bangkok had received any visas on Monday. They also said foreign staff inside the country were prevented from leaving Yangon.

"There are limits, if not bans, on staff going to the delta," Terje Skavdal of the U.N.'s humanitarian arm told reporters.

Uncertainty about the scale of the catastrophe continues more than a week after the cyclone.

The U.N. humanitarian agency said in a new assessment on Sunday that between 1.2 million and 1.9 million were struggling to survive in the aftermath of the storm.

It said the number of deaths could range up to 100,000 and "acute environmental issues" posed a threat to life and health.

Myanmar raised the death toll on Sunday to 28,458 dead and 33,416 missing from the storm on the night of May 2 and early on May 3.

Most of the victims were killed by the 12-foot (3.5 metre) wall of sea-water that hit the delta along with the Category 4 cyclone's 190 kph winds.

The cyclone raged through an area that is home to nearly half of the country's 53 million people and about 5,000 sq km of land remain under water.

FLASH APPEAL LAUNCHED

The United Nations launched on Monday in Bangkok its flash appeal for $187 million (96 million pounds) to support a minimum of 1.5 million people for at least three months. The WFP is seeking $56 million to provide food rations for 630,000 people for six months.

The more than one million worst affected lack food, water, and sanitation, face outbreaks of disease such as cholera, and heavy rains are predicted this week over the delta.

Three U.S. Navy ships are steaming toward Myanmar, and a French warship was expected near Myanmar's waters later this week, carrying 1,500 tonnes of rice that France said it wants to distribute directly to survivors.

Despite the alarm bells from the international community about the feeble cyclone relief effort, the junta kept its focus on a weekend referendum on a new constitution, part of a "roadmap to democracy" culminating in multi-party elections in 2010.

There is little doubt about the final result on an army-drafted constitution after an intensive propaganda campaign by the junta urging people to vote "Yes".