"The political vacuum provides the only space in which this 'micro' group can operate."

Mitchel McLaughlin: Attack linked to political vacuum

Nobody was injured in the explosion on Thursday which damaged the fence and an unmanned guardhouse at the barracks on the city's Waterside area.

Superintendent Ian Hamill said: "There is some damage to the perimeter fence of the barracks.

" No-one has been physically injured but, of course, it has been a shock to people working within the barracks."

Later on Thursday, the police found timing devices and detonators in Derry.

They were discovered during a security operation after men were seen running away from a car.

It is not known if it is connected to the attack on Ebrington barracks about three miles away.

The attack on the base was the second on a security installation in Northern Ireland in less than two months, heightening fears of a developing campaign by former IRA terrorists opposed to the Good Friday Agreement.

The Mayor of Derry, Pat Ramsey, has said he is dismayed at the attack and that those responsible are the enemies of the people of Ireland.

Ian Hamill: It has been a shock to people

Gregory Campbell, security spokesman for the anti-agreement Democratic Unionist Party, has visited the scene.

He said the blast bore similarities to the incident at Ballykelly, 12 miles away, in February.

Mr Campbell said: "In Ballykelly there was a breach of the security fence, with the bomb planted near sleeping quarters. Here it was beside a former guardhouse.

"It appears to have been outside the perimeter."

'Security a bit lax'

Mr Campbell also claimed that in recent months the base's watchtowers had not been manned.

"I get the impression that security has become a bit lax since the ceasefire," he said.

"This is confirmation of what we all knew was coming, a determined effort by paramilitary groups.

"When you look at the past few months it is very obvious that these groups - if they are splinter groups, if they are people who are leaving the Provisional IRA to join these dissidents or if the Provisional IRA is giving a wink and a nod to these dissidents - it is as plain as the nose on your face these people are developing terrorist capabilities."

Meanwhile, Irish Prime Minister Bertie Ahern has told the Irish parliament he believed dissident republicans were responsible for the bomb.

He said: "I would take the opportunity to unreservedly condemn the bomb."

He added their actions were "anti-republican".

He said both governments were determined to continue with their efforts to resolve the current crisis.

Progressive Unionist Party leader David Ervine said the attack on the army base could prompt a cycle of violence. Mr Ervine was speaking in Dublin prior to a meeting with Mr Ahern.

The governments in London and Dublin are still trying to inject momentum into the stalled Northern Ireland peace process before Easter in order to reinstate the suspended political institutions.