Two or three devices - described as petrol bombs by a witness - were thrown by the suspect, who was found dead at a nearby petrol station shortly later.

Another device found in the man's car was later made safe by the Explosive Ordnance Disposal Unit.

Two people who had been inside the centre suffered minor injuries in the attack.

Kent Police, which is leading the investigation, is not currently treating the incident as terrorism.

Home Secretary Suella Braverman described the attack as "distressing".

A photographer with Reuters news agency who witnessed the incident reported a man had thrown petrol bombs with fireworks attached before taking his own life.

Dover MP Nathalie Elphicke also said she understood the suspect had killed himself.

Police had been called at 11.22 GMT on Sunday to The Viaduct, Dover, where the devices thrown by the suspect had started a fire.

Speaking to LBC radio, Ms Elphicke said the motivation of the perpetrator was so far unknown, but the centre is "a well-known facility" where small boats arrive before people are taken 20 miles away to the Manston asylum processing centre in Kent.

The Dover site remained open but around 700 suspected migrants were moved to Manston - about 15 miles (24 km) away - for their safety during the initial stages of the police investigation.

Migrants were at the immigration centre following the incident in Dover

Posting to Twitter earlier, Ms Braverman said: "I am receiving regular updates on the situation.

"My thoughts are with those affected, the tireless Home Office staff and police responding. We must now support those officers as they carry out their investigation."

Conservative Dover MPMs Elphickesaid she was "absolutely shocked and appalled" by the incident and that "tensions have been rising" over the numbers of migrants arriving in the town.

"I have expressed my concerns over security of the centre in Dover," she said. "I don't think this is the appropriate place for a migrant-receiving centre. Dover is an extremely busy and open port."

Immigration Minister Robert Jenrick - who visited the Manston facility on Sunday - said he was being updated on the incident by Kent Police.