Four teenagers have been arrested in connection with a fire at an Islamic boarding school in Kent.
The four teenage males, two aged 17 and two 18, were arrested on suspicion of arson following the blaze at Darul Uloom School in Foxbury Avenue, Chislehurst on 8 June.
More than 120 pupils and staff members were evacuated from the school, but firefighters were able to extinguish the fire quickly.
Two people were treated at the scene for smoke inhalation, but they did not require hospital treatment. There was also minor damage to the school as a result of the blaze.
The arrests come after police announced they are stepping up security and patrols around "vulnerable" areas in London, following a series of suspected arson attacks on Islamic buildings and Mosques since the murder of Drummer Lee Rigby in Woolwich.
Cmdr Simon Letchford, of the Metropolitan Police, told the BBC's Today programme: "We have put additional police resources outside a number of premises which we think are vulnerable.
"Clearly this is a time for Londoners to come together after the tragic murder of Lee Rigby and we would encourage people to remain calm, to provide information to us on anybody who they believe is carrying out these criminal acts.
"We will do everything we can both to protect premises but also to bring to justice those who break the law."
Letchford added that since the death of Rigby on 22 May, there have been a significant number of Islamophobic attacks.
He added: "We normally have about one Islamophobic crime a day across London, we have seen around eight a day.
"Predominantly it's name calling, it's minor criminal damage but on some occasions, like the two arsons we have heard of, there are serious crimes."
Police probing Muswell hill attack
The four arrests came as counter-terrorist police continue to investigate a fire at an Islamic centre in Muswell Hill.
The letters EDL - the common acronym for the English Defence League - were scrawled on the Somali Bravanese Welfare Association building, according to firefighters who tackled the blaze. Police are investigating whether there is a link between the graffiti and the fire.
No one has been arrested in connection with the fire at the building, and police have said there is currently no connection linking the fire at Muswell Hill to the one in Chislehurst.
Earlier, Commissioner Sir Bernard Hogan-Howe said: "Detectives are working tirelessly to establish whether these fires were started deliberately, and if so, to catch those responsible.
"We should not allow the murder of Lee Rigby to come between Londoners. The unified response we have seen to his death across all communities will triumph over those who seek to divide us."