* Aquino under mounting pressure over aid distribution
* Police official who estimated 10,000 dead removed from post
* "There is utter devastation" - UN chief
* Relief efforts pick up with arrival of U.S. aircraft carrier
* Many bodies still on streets of Tacloban
The death toll from a powerful typhoon doubled overnight in one Philippine city alone, reaching 4,000, as helicopters from a U.S. aircraft carrier and other naval ships began flying food, water and medical teams to ravaged regions on Friday.
President Benigno Aquino has faced mounting pressure to speed up the distribution of aid and also come under criticism over unclear estimates of casualties, especially in Tacloban, capital of hardest-hit Leyte province.
A notice board in Tacloban City Hall estimated the deaths at 4,000, up from 2,000 a day before. The toll, written in blue marker on a whiteboard easel, is compiled by local officials who started burying bodies in a mass grave on Thursday.
Tacloban mayor Alfred Romualdez said some people may have been swept out to sea and their bodies lost after a tsunami-like wall of seawater slammed into coastal areas. One neighbourhood had a population of between 10,000 and 12,000, and now was completely deserted, he said.
The City Hall toll is the first public acknowledgement that the number of fatalities would likely far exceed an estimate given this week by Aquino, who said the loss of life from Typhoon Haiyan would be closer to 2,000 or 2,500.
Official confirmed deaths nationwide stood at 2,357 on Friday after the typhoon, one of the strongest ever recorded, roared across the central Philippines a week ago. Adding to the confusion, the United Nations, citing government figures, put the latest overall death toll at 4,460.
On Tuesday, Aquino said estimates of 10,000 dead by local officials were overstated and caused by "emotional trauma". Elmer Soria, a regional police chief who made that estimate to media, was removed from his post on Thursday.
A police spokesman said Soria was due to be transferred to headquarters in Manila. But a senior police official told Reuters he believed Soria was re-assigned because of his unauthorised casualty estimate.
U.S. HELICOPTERS TO AID RELIEF EFFORT
Survivors have grown increasingly desperate and angry over the pace of aid distribution, which has been hindered by paralysed local governments, widespread looting, a lack of fuel for rescue vehicles and debris-choked roads.
The dead are still being buried. Many corpses remain uncovered on roadsides or under splintered homes.
Foreign aid officials have called the disaster unprecedented for the Philippines.
"There is utter devastation. People are desperate for food, water, shelter, supplies and information about their loved ones," U.N. Secretary-General Ban Ki-moon told reporters on Thursday during a visit to Latvia.
"We are doing everything possible to rush assistance to those who need it. Now is the time for the international community to stand with the people of the Philippines."
The nuclear-powered USS George Washington aircraft carrier and accompanying ships arrived off eastern Samar province on Thursday evening, carrying 5,000 crew and more than 80 aircraft.
The carrier moved some fixed-wing aircraft ashore to make more room for the helicopters on its flight deck.
"One of the best capabilities the strike group brings is our 21 helicopters," commander Rear Admiral Mark Montgomery said in a statement. "These helicopters represent a good deal of lift to move emergency supplies around."
U.S. sailors have brought food and water ashore in Tacloban and the town of Guiuan.
The carrier is moored near where U.S. General Douglas MacArthur's force of 174,000 men landed on Oct. 20, 1944, in one of the biggest Allied victories of World War Two.
Another U.S. aircraft carrier, the USS Abraham Lincoln, led a massive aid operation off Indonesia's Aceh province after the Indian Ocean tsunami in 2004.
Aquino has been on the defensive over his handling of the storm, given warnings of its projected strength and the risk of a storm surge, and now the pace of relief efforts.
He has said the death toll might have been higher had it not been for the evacuation of people and the readying of relief supplies, but survivors say they had little warning of any seawater surge.
Tacloban city administrator Tecson John Lim, who on Sunday also estimated 10,000 likely died, said Aquino may be deliberately downplaying casualties.
"Of course he doesn't want to create too much panic. Perhaps he is grappling with whether he wants to reduce the panic so that life goes on," he said.
The preliminary number of missing as of Thursday, according to the Red Cross, remained at 22,000. That could include people who have since been located, it has said.
'WHO IS IN CHARGE?'
Tacloban's main convention centre, the Astrodome, has become a temporary home for hundreds of people living in squalor. Families cooked meals amid the stench of garbage and urine. Debris was strewn along rows of seats rising from dark pools of stagnant water.
"We went into the Astrodome and asked who is in charge and just got blank stares," said Joe Lowry, a spokesman for the International Organisation for Migration, which is setting up camps for the displaced.
Survivors formed long lines under searing sunshine, and then torrential rain, to charge mobile phones from the only power source available - a city hall generator. Others started to repair motorbikes and homes. A rescue worker cleared debris near a wall with the spray-painted words: "We need food".
Outside Tacloban, burials began for about 300 bodies in a mass grave on Thursday. A larger grave will be dug for 1,000, Lim said.
The city government remains paralysed, with an average of just 70 workers on duty, compared with 2,500 normally, he added. Many were killed, injured, lost family or were too overcome with grief to work.
More than 920,000 people have been displaced, the United Nations said. But many areas still have not received aid.
"It's true, there are still areas that we have not been able to get to where people are in desperate need," U.N. humanitarian chief Valerie Amos told reporters in Manila. "I very much hope that in the next 48 hours, that will change significantly.
"Yes, I do feel that we have let people down because we have not been able to get in more quickly."