Worried friends and relatives have gathered at Nairobi's airport Friends and relatives

The flight, which originated in Ivory Coast, is believed to have come down in dense jungle after taking off in heavy rain from Douala en route to Nairobi.

Searchers using helicopters are focusing o­n the Lolodorf area after reports of an explosion there.

The missing come from more than 20 countries, including five Britons.

The Boeing 737-800 was just six months old and part of a new fleet bought by the airline.

The presumed crash will raise questions about whether other aircraft will be taken out of service, the BBC's Karen Allen reports from Nairobi.

Kenya's national carrier has a good safety record but 169 people died when o­ne of its planes crashed in 2000.

'Confusion'

Flight KQ 507 originated in Abidjan and left Douala, Cameroon, at 0005 o­n Saturday (2305 GMT Friday), being due to reach Nairobi at 0615 (0315 GMT).

The last communication with the missing plane was received by the control tower in Douala, o­n the coast, shortly after take-off, Kenya Airways said.

A distress signal was later sent out by the plane, Kenyan Airways chief executive Titus Naikuni said, adding that this would have been sent out automatically.

A BBC correspondent in Lolodorf says the situation there has been chaotic, and heavy rains o­n Saturday prevented a ground search from taking place.

Aerial searches were called off after dark o­n Saturday but are expected to resume o­n Sunday.

'Anxious and desperate'

Kenyan Transport Minister Chirau Ali Makwere - who is leading a team of Kenya Airways and government officials to Douala - said it was too early to determine what had happened to the plane.

NATIONALITIES OF MISSING 35 Cameroon 15 India 9 Kenya (crew) 7 South Africa 6 China 6 Ivory Coast 6 Nigeria 5 Britain 3 Niger 2 Central African Republic 2 Democratic Republic of Congo 2 Equatorial Guinea 1 Ghana; Sweden; Togo; Mali; Switzerland; Comoros; Egypt; Mauritius; Senegal; Congo; Tanzania; US; Burkina Faso 3 unidentified Source: Kenya Airways

"We need to get information from the technical experts as to whether it was occasioned by the weather or pilot error or mechanical fault," he was quoted by the Associated Press as saying.

A crisis management centre is now working in Nairobi.

Anthony Mitchell, a respected and well-known Associated Press journalist based in Nairobi, is thought to be among the missing Britons.

There has been no confirmation from the Foreign Office.

On Saturday, there were distressing scenes at Nairobi's Jomo Kenyatta International Airport where a number of worried friends and relatives gathered.

"We can o­nly hope for the best and pray... We're anxious and desperate," o­ne man said.

The Kenya Airways website says the fleet is 23-strong. It is 26%-owned by Air France-KLM.

In January 2000 a Kenya Airways plane crashed into the sea after taking off from Abidjan airport in Ivory Coast killing 169 people. There were 10 survivors.