The disclosure came as a top cop said the officer injured in the car bomb attack in Castlederg is determined to defy the bombers and get back to work.

Assistant Chief Constable Judith Gillespie also revealed that the injured officer is looking forward to leaving hospital within weeks.

She was speaking in Londonderry yesterday as the PSNI gathered to honour winners at the Policing with the Community awards in the city.

She said that it was too early to confirm reports that the device, which exploded under the car of the officer last Monday night as the policeman made his way to Enniskillen for a shift, contained semtex.

This claim was made by the Real IRA, who said late last week that they were responsible for the attack, which left the 26-year-old, thought to originally be from Omagh, with serious leg injuries.

A PSNI spokesman said yesterday: "We haven't yet established what the explosives were. We are still carrying out forensics tests on the device."

"We have still not discussed what sort of device this was and the investigations are still at an early stage," she said.

"We are aware of the Real IRA claim but we are not in a position to make a comment at this stage."