The "Real IRA" has said it planted a booby-trap bomb defused at a British army base in Co Derry.
The bomb, described as an "anti-handling device", was left attached to a rubbish bin near the married quarters at Shackleton Barracks in Ballykelly.
"The suspicious object found... this morning has been confirmed as an explosive device designed to kill or maim anyone who moved it," a PSNI spokesman said. "An investigation is under way to establish how it was planted."
The "Real IRA" said it had planted the device in a statement telephoned to the Derry News, using a recognised codeword.
"Armed volunteers breached security at the base by cutting through two fences," said the statement.
"The only good fortune on the part of the British was that they discovered the hole in the fence and began a search before the device was detonated, preventing almost certain British army casualties."
More than 100 families were evacuated from their quarters after the device was discovered around 9 a.m., a British army spokesman said. Army bomb disposal experts were called in and a controlled explosion was carried out.
Ms Jane Kennedy, the Northern Ireland Security Minister, hit out at the bombers.
She said: "These people have shown scant regard for the lives of the men, women and children who could have been killed or maimed by their actions.
"They are living in the past and must be condemned by all right-thinking people."
The Ballykelly camp is occupied by the 1st Battalion The Green Howards whose headquarters are in North Yorkshire. A joint police-army investigation into the incident will include the examination of CCTV footage from cameras which are located both inside and outside the heavily guarded camp.