(CNN) -- Northern Ireland police said Saturday they were investigating a car bomb that exploded overnight in the city of Derry, about 70 miles northwest of Belfast.
No one was hurt in the bombing, which happened in the city center shortly after midnight and left the car on fire, police said.
The explosion followed an attack Friday in which masked gunmen in Belfast fatally shot a man at point-blank range on a busy shopping street.
Police said at least two men approached Robert Moffett, 43, and shot him in the face on Shankill Road, a major thoroughfare in Belfast. The attack happened at lunchtime as the street was packed with people, police said.
"To murder this man was an evil act, but to do it in the middle of the day, on a busy road full of local people going about their normal business, only adds to the horror and the sense of shock and revulsion," said Owen Paterson, secretary of state for Northern Ireland.
"Anyone who would carry out such a barbaric act is a threat to the whole community."
The shooting happened in front of children, Britain's Press Association and the Belfast Telegraph reported.
"This cold-blooded murder in broad daylight will shock people across Northern Ireland," said Northern Ireland Justice Minister David Ford. "Those who carried out this killing are to be condemned."
Police said a 40-year-old man, whom they did not name, had been arrested in connection with the shooting.
A police spokesman said the attack was a "chilling reminder of a violent past that everyone in the community hoped we had left behind."