The plane crashed near Niete, south of the Cameroonian port town of Kribi and north of the border with Equatorial Guinea, after taking off from Cameroon's second city of Douala.

In Nairobi, Kenya Airways Group Managing Director Titus Naikuni said authorities in Cameroon had picked up an automatic distress signal from the area where the plane went missing.

Kenyan government spokesman Alfred Mutua told a news conference the signal was coming from an area about 35 nautical miles southwest of Douala. "They have a helicopter in the area, " he said, adding there had been no report yet from that mission.

The 737-800 airliner, which began its journey in Ivory Coast's main city Abidjan and stopped over in Cameroon, was carrying 105 passengers and nine crew. Officials had earlier said there were 106 passengers.

The airline said there were 34 Cameroonians, 15 Indians, seven South Africans, six Chinese, five Britons and one American among the passengers, the bulk of whom were from African countries. The nine crew were all Kenyans.

The company said the Douala control tower had received the last message from the aircraft right after takeoff.

Kenya Airways set up a crisis centre to monitor events and a passenger information centre at a hotel in Nairobi.

The carrier generally has a good safety record on a continent where air accidents are above the world average.

The plane was six months old and had no history of problems, Naikuni said.

Kenyan media reported there was rain in Douala when the plane took off.