A cargo plane crashed into a residential area of Pointe-Noire, the Republic of Congo's economic capital, killing at least 19 people, officials said.

"We have registered 19 deaths and 14 injured. For the moment there are more dead than injured. These are still preliminary figures," National Civil Aviation Agency director general Michel Ambende said.

"We don't know yet if the toll will grow. Searches are continuing," said Mr Ambende, who was at the scene of the accident.

The plane crashed in an area that includes the district mayor's office, the offices of a television station, a private elementary and secondary school, and a popular stadium.

Mr Ambende earlier said the plane crashed on landing after the control tower gave authorisation for it to land, adding there was "a lot of damage" at the scene.

An airport source at the scene says the plane was an Antonov run by Trans Air Congo airline.

Police say the plane had been carrying four crew members and five "clandestine" passengers.

"I can see smoke coming from the scene of the accident," Pointe-Noire resident Emile Mboussa, 39, told AFP.

"I can see ambulances passing. I do not know if they are carrying dead or wounded."

Another witness, English teacher Serge Bakala, said the plane came down between the Roy and Kitoko areas in the city's Mvou-Mvou district.

Another witness told AFP the city was "in shock. It's apocalyptic."

Trans Air Congo is a passenger and cargo airline based in Brazzaville, the capital of the Republic of Congo which is among the five top oil producers in sub-Saharan Africa.

The country has banned Antonov planes from carrying passengers following previous accidents.

In June 2010, Australian mining tycoon Ken Talbot and 10 colleagues were killed in a plane crash in the north-west of the country and in August 2009 six crew members were killed when an Antonov cargo plane crashed at a cemetery on the outskirts of Brazzaville.