LUANDA, Angola (AP) _ The United Nations called Sunday for a 48-hour cease-fire between the Angolan government and UNITA rebels to allow an investigation team to reach the site of a U.N. aircraft that crashed with 14 people on board this weekend.

The C-130 aircraft went down in an area 310 miles southeast of the capital Luanda where the government army has been fighting UNITA for nearly a month.

It was not known if there were any survivors.

U.N. spokesman Hamadoun Toure said there was no immediate information on the cause of the crash. He cited government sources in the central highland city of Huambo as saying they had seen a plane go down in flames shortly after takeoff from there and that it had crashed 25 miles away in Vila Nova.

An Angolan government plane was shot down Dec. 14, just north of another central highland city of Kuito, killing 10 people. It was not clear who had fired at the aircraft.

Onboard the plane that crashed Saturday were four Angolans, two Russians, an Australian, an Egyptian, a Cameroonian, a Zambian, a Namibian, a South African, a Bolivian and a Filipino.

Eight were members of the U.N. Observer Mission in Angola and two were employed by a private communications company, Dinacom, working with the United Nations, Toure said. The other four were the plane's crew.

The World Food Program reacted to the crash by suspending food delivery flights throughout Angola until Wednesday, pending more information on the crash, according to Brenda Barton, a spokeswoman for the organization in the Kenyan capital of Nairobi.

The U.N. military observers are charged with monitoring a 1994 peace accord that is severely threatened by fighting between the government and UNITA rebels that flared up again three weeks ago.

Kuito and Huambo, which lie some 80 miles apart, have served as a stage for heavy battles between UNITA and the government for nearly a month.

Neither the government nor the rebels responded to the U.N. call for a cease-fire, Toure said.

U.N. Secretary-General Kofi Annan appealed to the Angolan government and to UNITA to allow members of the U.N. Observer Mission in Angola to go to the crash site and assist in search and rescue operations, a spokesman said in a statement.

The plane, owned by TransAfric and chartered by the United Nations, was headed for Saurimo, in the province of Lunda Sul, about 390 miles east of Huambo, Toure said. The four-engine C-130, one of the most widely used military transport planes, can carry up to 92 people.

The U.N. Security Council has expressed dismay that Angola appears headed back to civil war, which has ravaged the southern African nation since the country's 1975 independence from Portugal.

Diplomats have been unable to get both sides to adhere to a 1994 peace accord. The agreement called for UNITA, whose name is a Portuguese acronym for the National Union for the Total Independence for Angola, to disarm and to hand areas under its control to the government. However, lingering hostility between the two sides has hindered implementation of the deal.

The council on Wednesday again accused Angolan rebel leaders of undermining the peace process and demanded an immediate end to the fighting.

WFP's Barton said that food distribution to approximately 400,000 Angolans displaced by the conflict would not be interrupted by the grounded flights.

But she said the situation was ``grave'' because air cargo is the only way to replenish supplies. Commercial food supplies via roads have been shut down by the fighting.