Mediterranean principality Monaco was hit by its first bomb blast overnight when an explosion went off at its main soccer stadium.
"A criminal link has been established. We were fortunate because no one suffered any bodily harm," Monaco Public Works Minister Jose Badia said of the blast, which damaged some offices but caused no casualties.
Mr Badia said no one had claimed responsibility for the blast, which occurred early yesterday at the Stade Louis II, AS Monaco's home ground.
A source close to the police investigation said the bomb weighed one to three kilogrammes. The explosives were placed in an air vent accessible from outside the stadium.
Monaco, which borders the Mediterranean Sea on the southern coast of France, is a high-security haven for jet-setters and tax exiles.
The safety of residents and their property is an important economic factor for the principality. Many residents are wealthy foreigners who have chosen to live in Monaco because of its crime-free reputation.