A small plane crashed on takeoff at Southend Airport in London, with witnesses saying they saw a 'large fireball' following the mishap.

Several images of the mishap were posted online, where a thick cloud of black smoke could be seen at the spot of the accident.

In a statement posted on Facebook, the airport described the event as 'serious'.

"We can confirm there has been a serious incident at London Southend Airport this afternoon involving a general aviation aircraft," the airport said in a statement.

The plane involved was a medical transport jet operated by Zeusch Aviation, and was equipped with medical systems for transporting patients, Daily Star reported.

Also Read: Preliminary investigation report shows both engines of crashed Air India flight shut down seconds after take-off

No details about the condition of the pilots have been shared so far.

Describing the mishap, Essex Police said all emergency services attended the scene of an incident involving one plane at about 4pm.

Police confirmed the plane crashed after it had taken off.

"Flights at the airport were quickly grounded to ensure work could immediately begin on extinguishing the flames as quickly as possible," police said.

Chief Superintendent Morgan Cronin said: "In these very early stages it is vital we gather the information we need, and continue supporting the people of Essex."

"We are working closely with all at the scene, as well as the Air Accident Investigation Branch, to establish what has happened today and why," Morgan said.

Eyewitness says pilots waved to families watching planes

One man, who was at the airport with his wife and children, told Sky News the plane crashed within seconds of taking off.

John Johnson said the pilots "waved" at his family as they taxied the aircraft.

"We all waved [back] at them," he continued. "They carried on taxiing to their take-off point and turned around.

"Then they throttled up the engines and passed by us. The aircraft took off and within a few seconds it had a steep bank angle to its left."

The aircraft then "almost seemed to invert and unfortunately crashed," he said. "There was a large fireball."

Airport to remain closed

Meanwhile, Southend Airport said the airport will remain closed until further notice.

"All flights to and from the Airport have been cancelled while Police, emergency services and air accident investigators are attending the incident," the airport wrote in a statement.

David Burton-Sampson, the MP for Southend West and Leigh urged people to keep away from the area.

"I am aware of an incident at Southend Airport. Please keep away and allow the emergency services to do their work. My thoughts are with everyone involved," he said.