A Ghanaian is believed to be among 114 people aboard a Kenya Airways plane that has crashed in southern Cameroon.
The flight, which originated in Ivory Coast, was reported missing on Saturday after it failed to arrive in Nairobi.
The BBC's Karen Allen in Nairobi says the Boeing 737-800 is part of a new fleet bought recently by the airline.
Kenya Airways has not confirmed the crash. It said people of various nationalities were on board, including five Britons.
Flight KQ 507 originated in Abidjan in Ivory Coast and left Douala in Cameroon at 0005 local time (0105 GMT) on Saturday. It was due to arrive in Nairobi at 0615 (0315 GMT), but came down near the town of Niete, Cameroon state radio said.
Kenya Airways only said the last communication with the missing plane was received by the control tower in Douala, Cameroon, shortly after take-off.
The company's chief executive, Titus Naikuni, said a distress signal was detected on the west coast of Africa and a Cameroon search and rescue team dispatched at about 0900 GMT.
Poor weather is reported to be hampering the rescue effort. Mr Naikuni said a team of Kenya Airways and government officials would leave for Douala later on Saturday.
A Crisis management centre has been set up in Nairobi. A number of worried friends and relatives have been gathering at the capital's Jomo Kenyatta International Airport.
"We have been told to sit and wait," one relative of a passenger on the plane told AFP news agency.
"A lot of people are crying, people are asking what is happening."
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.
Nationality of passengers
9 Kenya (crew)
7 South Africa
6 Ivory Coast
2 Central African Republic
2 Democratic Republic of Congo
1 Ghana; Sweden; Togo; Mali; Switzerland; Comoros; Mauritius; Senegal; Congo; Egypt; Tanzania; US; Burkina Faso