Two men were arrested by police in Derry yesterday as part of their investigations into the discovery of a 1,200 lb van bomb in the city on Sunday morning.
The two, aged 33 and 24, were arrested from their homes in the city's Creggan area 24 hours after the bomb was found at Clooney Road by members of a police patrol.
Supt Dawson Cotton, who is leading the investigation, disclosed yesterday that the van had been bought recently and he believed the bombers had it in their possession since last Friday.
"This bomb was driven through a built-up area. We're talking about a bomb that was twice the size of the bomb which murdered so many people in Omagh.
"It was a massive bomb and those responsible for assembling it and driving it showed absolutely no regard for the human rights of the people of this city."
The Minister for Foreign Affairs, Mr Cowen, described the arrests as the latest example of successful co-operation between security forces north and south of the Border.
He said there was a small number of people who wanted to derail the peace process but that there was "a very intensive effort to prevent this".