YAOUNDE, Cameroon -- Cameroon observed a day of mourning Saturday for more than 1,700 people killed by a cloud of poison gas that belched from a volcanic lake, as relief teams struggled to distribute international aid.
All non-relief work was forbidden across the grieving west African nation as flags flew at half-staff, special Requiem services were held and state-run radio broadcast only solemn classical and Cameroonian music.
President Paul Biya ordered the day of national mourning Friday. In Geneva, the United Nations raised the official death toll from the Aug. 21 toxic gas leak on Lake Nios in Northwest Province from 1,534 to 1,746.
Radio Cameroon broadcast a song called 'Day of Mourning,' speaking of a 'murderous land that turned on its own people,' as planeloads of medicine, food and tents were piled up at Bamenda airport - the nearest to the disaster.
In a bid to better control the flood of aid, authorities ordered Bamenda closed to all but Cameroonian military aircraft, meaning goods had to be transfered from foreign aircraft to the air force inYaounde and Douala.
An official of the World Health Organization in Cameroon said antibiotics, pain-killers and other drugs were still needed for the sick - many suffering from pneumonia, sulfur burns or respiratory problems in two packed hospitals.
Relief workers said air and land transport facilities were stretched to the breaking point in handling the aid and getting it swiftly to the injured and homeless, despite a shortage of trucks and airport landing and storage space.
'You have to understand that Cameroon has never had anything like this before so was not very well prepared,' said a Western diplomat in the city of Douala. 'They are generally doing the best they can, but it is quite a struggle.'
Military teams Thursday finished burying most of the dead where they fell, but soldiers were finding it difficult to dispose of all the bloated cattle carcasses that pose a health hazard if left to rot.
The toxic gas -- identified by a French expert on the scene as carbon dioxide with a trace of hydrogen sulfide -- injured about 500 people and killed about 7,000 cattle in a 6-mile area around the volcanic crater lake.
Officials had hoped all the cattle would be disposed of before the weekend but the numbers and lack of equipment made that impossible. Some local drinking water is already contaminated -- apparently by the decaying carcasses.
Haround Tazieff, a French vulcanologist who toured the scene, said a leak of steam at high pressure onto the lake floor forced the cloud of gas to the surface of Lake Nios. U.S. and Japanese scientists are also surveying the area.
Tazieff said more gas probably is trapped under the sediment so 'any eventual return of the population to this area is absolutely prohibited.' Some 3,000 people had to leave their homes.
The army has ordered people to stay out of the region, which is dotted with lakes similar to Nios, and has not set a date for them to return. Many moved to temporary missionary-run camps or moved in with friends and relatives.
French scientists in Paris have said they believe the victims died almost instantly after breathing the carbon dioxide gas.
Survivors have described struggling to breathe the hot gas and then falling unconscious.
Some foreign relief officials and doctors have said the final death toll could be as high as 2,000 as many bodies were buried last weekend by relatives and villagers before they could be counted by the army or U.N. representatives.