BELFAST, Northern Ireland (AP) _ A bomb exploded early today outside the top-security Crumlin Road courthouse in Belfast in the second such attack in eight days, police said.

Also today, two masked men shot to death a man working in a store at central Belfast's Smithfield Market, police said.

The man was dead on arrival at Royal Victoria Hospital, said a spokesman for the Royal Ulster Constabulary. Police would not identify the victim, but Press Association, the domestic British news agency, said he was Ian Catney, 25, a Roman Catholic who was working in his mother's store.

There was no claim of responsibility for the shooting or the bombing.

The area in which the explosion occurred had been evacuated and there were no injuries, said a spokesman for the Royal Ulster Constabulary, requesting anonymity. Damage was slight, he said.

The bomb had been placed in a hijacked car taken from a family held hostage in the Springfield Road area of mainly Roman Catholic west Belfast, he said.

Gunmen opened fire on a British army post atop the Crumlin Road courthouse and prison building on Jan. 10 and left a car bomb in a hijacked car nearby. There were no injuries in that incident, and bomb experts defused the bomb.