(CNN) -- A car bomb exploded early Tuesday in front of a police station in Londonderry, Northern Ireland, but there were no injuries, police said.
Police later said it was a 200-pound bomb. They had received a warning that it would explode in 45 minutes, but it went off in about half that time, police said.
If officers hadn't moved in quickly to evacuate those in the immediate area, they said, the bomb would have caused deaths.
The blast happened after two men, one of whom had a gun, hijacked a taxi in the early hours of the morning and placed an object inside the vehicle, the Police Service of Northern Ireland said. They told the driver to head toward the Strand Road Police Station.
The driver got out of the taxi before the device exploded at 3:20 a.m. (10:20 p.m. ET), police said.
The blast damaged the station and several homes in the area, they said.
A series of such attacks has been reported in Northern Ireland this year, but none has caused serious injuries. The attacks are often blamed on dissidents who oppose the 1998 Good Friday peace settlement.
There have been no claims of responsibility for Tuesday's bombing.
Journalist Peter Taggart in Belfast, Northern Ireland, contributed to this report.