Two soldiers and a policeman were injured in the nationalist Short Strand area of east Belfast at 10.20pm. One of the soldiers had facial and body injuries, while the policeman was injured in the leg.
They were members of a joint army-RUC foot patrol making its way through the district, one of the few Catholic areas in east Belfast.
The Short Strand area has a republican presence but has been largely quiet even since the ending of the IRA's ceasefire in February last year.
Earlier in the day, a soldier was slightly injured in a grenade attack in north Belfast. The explosion blew an armoured panel off a Land Rover as troops drove through the Ardoyne district. The injured soldier, a member of the 2nd Battalion, the Royal Tank Regiment, was on observation duty, standing with his head through the roof of the vehicle.
A number of windows in nearby houses were blown in by the force of the explosion.
In another incident the IRA telephoned a radio station to say two coffee- jar bombs had been thrown at troops in the Poleglass district of west Belfast but had not exploded.
Army experts were expected to move in to search the area at first light this morning.
Speaking after the Ardoyne attack, the Northern Ireland Office minister, Michael Ancram, said it was another example of "murderous terrorism in order to try to achieve political ends. I condemn it roundly - we will never bow to terrorism."
The Northern Ireland security minister, Sir John Wheeler, later condemned the Short Strand explosion.
"The IRA have once again demonstrated their contempt for human life and democracy," he said.Reuse content