An Ethiopian Airlines plane crashed on Sunday morning on its way from Addis Ababa to Nairobi, Kenya, the airline has confirmed.
In a statement, the airline said it believed that 157 people were on board.
"It is believed that there were 149 passengers and eight crew on board but we are currently confirming the details of the passenger manifest for the flight," it said.
It added that search and rescue operations had been launched and that its officials were also checking for information on survivors and casualties.
"Staff will be sent to the accident scene and will do everything possible to assist the emergency services," the statement said.
The airline also said it would set up an information center and provide a phone number for family and friends.
Ethiopian Airlines identified the flight number as ET 302/10 and said the crash took place around Bishoftu, formerly known as Debre-Zeit.
The plane's other identification details were given as B-737-800MAX, registration ET-AVJ.
The aircraft left Bole International Airport in the Ethiopian capital at 8.38am local time and lost contact six minutes later.
The Boeing 737-800MAX is the same type of plane as the Indonesian Lion Air jet that crashed last October, 13 minutes after takeoff from Jakarta, killing all 189 people on board.
The last major accident involving an Ethiopian Airlines passenger plane was a Boeing 737-800 that exploded after taking off from Lebanon in 2010, killing 83 passengers and seven crew.
Earlier on Sunday, the office of Ethiopian Prime Minister Abiy Ahmed reported the accident without giving details.
"The Office of the PM, on behalf of the government and people of Ethiopia, would like to express it’s deepest condolences to the families of those that have lost their loved ones on Ethiopian Airlines Boeing 737 on regular scheduled flight to Nairobi, Kenya, this morning," the PM tweeted.
Kenyan leaders, President Uhuru Kenyatta and Orange Democratic Movement leader Raila Odinga, also tweeted their condolence messages.
President Kenyatta wrote, "We are saddened by the news of an Ethiopian Airlines passenger aircraft that is reported to have crashed six minutes after takeoff en route to Kenya. My prayers go to all the families and associates of those on board."
Mr Odinga said, "My deeply felt condolences to the people of Ethiopia following the crash of the Ethiopian Airlines plane. My prayers are with the families and relatives of victims."
As condolence messages were sent, Ethiopian Airlines issued the following as emergency hotlines: (251)11 5 17 87 33, (251)115 17 47 35 and (251)11 5 17 41 00.
For all information necessary, friends and family were asked to call (251)11 5 17 89 45, (251)11 5 17 89 87, (251)11 5 17 82 31 and (251)11 5 17 85 58
The airline flies to many destinations in Africa, making it a popular carrier in a continent where many airlines fly only from their home country to destinations outside Africa.
It has a good reputation for safety, although in 2010 one of the company's aeroplanes crashed in the Mediterranean Sea shortly after leaving Beirut.
The incident killed 90 people on board.
The airline's highest fatalities to date came in a November 1996 crash during a hijacking on a flight from Addis Ababa to Nairobi.
One of the aeroplane's engines stopped when the fuel ran out and although pilots attempted an emergency water landing, they hit a coral reef in the Indian Ocean and 123 of the 175 people on board were killed.
The US State Department on March 8 issued a security alert warning its nationals not to arrive or depart Bole International Airport on March 10 because planned calls for a protest at Meskel Square.
The US Embassy cited many protests that have occurred in many parts of the Oromia region, where Meskel Square is, since March 6.
Responding to a Twitter user identified as Frehat Negash, who wanted to know if the security alert was linked to the ET302 plane crash, the US Embassy said the notice was “related to concerns about impeded traffic in the city due to expected protests.
“The restriction on travel to and from Bole Airport was lifted through Consular notification system yesterday evening,” the embassy said through its @USEmbassyAddis handle.
Additional reporting by AFP, BBC and Joel Muinde.