No group claimed responsibility for today's ambush in an Irish Catholic part of north Belfast. But Irish Republican Army splinter groups regularly target police as part of their efforts to undermine Northern Ireland's peace process.
A senior policeman, Chief Inspector Andy Freeburn, says it was "sheer good fortune" that both officers were not killed or wounded.
The officers reported two distinct blasts as they stepped out of their vehicle shortly after midnight.
Police sheltered local residents overnight in a nearby gymnasium. The road remained cordoned off today morning as forensics officers collected bomb remains for analysis and searched the area for potential unexploded devices.