Madrid rocked by car bomb explosion

A car bomb has exploded in Madrid city centre.

There are thought to be several injuries but a Madrid ambulance spokesman said it is not known how many.

A fire spokesman said about 15 cars have been destroyed in the blast on the north-eastern outskirts of the city centre.

The explosion occurred shortly after 9am (8am Irish time) on Corazon de Maria street on the north-eastern outskirts of the city centre.

According to reports, the bomb went off close to the Spanish headquarters of the computer multinational IBM.

The area, close to the main highway for Madrid's airport and Barcelona city, is one of the busiest in Madrid with many office and residential buildings.

"I heard a terrible explosion and thought a building had collapsed," a woman eyewitness said.

No group has so far claimed responsibility for the blast.

The armed separatist group ETA has frequently carried out car-bomb attacks in its 33-year campaign for independence of the northern Basque region.

The group, which has killed 800 people in its campaign, was blamed for a car-bomb blast in Madrid last month which injured 17 people.

The explosion comes after more than a dozen members of two Eta linked groups were arrested last week.