The buildings worst hit by the explosion of a 200lb proxy bomb which targeted Strand Road police station in Derry may have to be demolished.
Yesterday, shop owners returned for the first time to the scene of the blast to survey the extent of the damage.
A taxi driver hijacked at gunpoint was forced to deliver the bomb to Strand Road in the early hours of Tuesday morning.
The PSNI had received a telephone warning by a group claiming to be from Óglaigh na hÉireann, a dissident republican organisation, that the device would explode in 45 minutes but it went off just 23 minutes later.
The area remains cordoned off, while the full extent of the damage caused to the buildings is being assessed by engineers.
Derry City Centre Manager, Jim Roddy, says the commercial impact of the attack on the city will be "massive".