An organisation calling itself Oglaigh na hEireann has claimed it was behind Tuesday's car bomb attack on Strand Road police station in Londonderry.
In a statement, the organisation also said it had attempted to bomb the police barracks on the previous day.
It said that attack had not gone ahead after two taxi drivers "refused to cooperate with instructions".
Two hundred pounds of homemade explosives were used in Tuesday's car bomb attack.
No-one was injured in the attack which happened at 0320 BST, but several businesses were badly damaged.
PSNI divisional commander Steve Martin said it was fortunate no-one was killed because the device went off more than 20 minutes before a warning said it would.
He also revealed that a policeman risked his own life when he walked past the bomb twice to bring to safety staff at a nearby fast food shop.
Police said the roads around the station were likely to remained closed until Thursday.
The cordon point at Strand Road/Clarendon Street has been moved to the Strand Road/Asylum Road junction.
Boating Club Lane has now been reopened up to the junction of Strand Road.
The other point at Strand Road/Lawrence Hill remains in place.