A man has been arrested in connection with an explosion inside a World War II bunker which injured two teenage boys in Faringdon, Oxfordshire.
The 62-year-old was arrested on suspicion of causing an explosion with the intent to cause grievous bodily harm.
He has been bailed pending further inquiries until 7 July.
At around 1500 BST on Sunday, the boys suffered burns after an explosion in the pillbox in London Road.
They remain in the Frenchay Hospital in Bristol in a stable condition.
It is thought the two 15-year-olds were smoking inside the pillbox when one of them threw a cigarette into a bucket sparking a "flash fire".
Local Commander, Ch Insp Andy Boyd, said: "I appeal to anyone who was in Faringdon over the weekend and saw anybody acting suspiciously near the pillbox between Saturday morning and Sunday afternoon to contact police.
"I would like to reassure the community of Faringdon that we are treating this as an isolated incident and the neighbourhood team will be carrying out high visibility patrols in the area."