The home secretary, Priti Patel, has suggested that a fire at a former military barracks used to house asylum seekers was set deliberately as she comes under mounting pressure to shut the site. Images posted online showed thick smoke billowing from one of the blocks at Napier barracks near Folkestone. The facility has the capacity to hold 400 people but in recent days some have been transferred to hotels after a Covid-19 outbreak. Kent fire and rescue service said eight fire engines had been sent to the barracks to deal with the blaze, and advised people living and working in the surrounding area to close their windows and doors as a precaution against smoke. Kent police said there were no reported injuries and “enquiries remain ongoing to determine the cause of the fire and establish whether any offences have been committed”. But pre-empting the conclusion of any police investigation, Patel said in a statement: “The damage and destruction at Napier barracks is not only appalling but deeply offensive to the taxpayers of this country who are providing this accommodation while asylum claims are being processed. “This type of action will not be tolerated and the Home Office will support the police to take robust action against those vandalising property, threatening staff and putting lives at risk. This site has previously accommodated our brave soldiers and army personnel – it is an insult to say that it is not good enough for these individuals.” Military personnel have not been accommodated on the site for years. Clare Mosley, founder of Care4Calais, said: “For a British home secretary to accuse and castigate ordinary people when the facts of this incident are not yet even known is shocking and disturbing. It shows a senior government minister operating at the gutter level of gossip and hearsay, and at a time of heightened anxiety and tension across society, she should be ashamed of herself. “But make no mistake, this not simply a careless, off-the-cuff emotional response. It is a misleading, opportunistic smoke screen concocted to deflect attention from the multiple warnings she has had about what was clearly going to happen at Napier barracks.” Earlier on Friday, several organisations including Freedom from Torture, Choose Love/Help Refugees, Detention Action, Doctors of the World and Helen Bamber Foundation wrote to the home secretary urging her to close the barracks. Thousands of people signed a petition urging Patel to shut the site, which has been dogged by allegations of overcrowding, poor hygiene, significant risks posed by Covid-19, limited access to healthcare and legal advice, and cover-ups. At least 120 men at the barracks have tested positive for coronavirus this month, prompting panic among residents, some of whom took to sleeping outside in sub-zero temperatures for fear of infection. There are 16 blocks in the camp, most of which hold up to 28 people. The blocks have two toilets and showers and the men eat together in a communal canteen. One asylum seeker at the site said: “Some of us are really scared. The roof is on fire and parts of it fell down. The firefighters arrived at the camp. They turned off all the electricity here and some of us are really frightened. Everything is out of control. People are watching the block burning. “The security guards, the staff and the camp managers escaped. Now we are all in the camp without the staff, without anyone else.” On Friday the men received communications from Clearsprings, the private contractor that runs the site on behalf of the Home Office, informing them they would be moved to other blocks to allow “further deep cleaning” and to help control the spread of Covid-19. The correspondence said there were still men on the site with Covid-19 and they must continue to stay there. Until the recent outbreak, the men had been able to come and go from the barracks. The men were told that once moved to a new block they would be in a new “bubble” and must not mix with people outside their designated bubble. Several protests have taken place over the conditions and lack of communication from authorities over the length of the men’s stay. Many claim they were told they would be there for no more than a month and have now been there for four months.