Spanish police have cordoned off streets around the headquarters of the ruling conservative Popular Party and are searching for possible explosives after a man rammed his car into the building.

A police robot could be seen close to the Genova Street office in downtown Madrid, and ambulances lined a nearby road in apparent preparation for an emergency situation.

A police spokeswoman said bomb disposal experts were searching the area. She said police found two gas cylinders in the car and an unidentified substance.

She said the driver has been arrested.

Leading Cadena SER radio cited police as saying said the man admitted attacking the party headquarters Friday because he had lost his business in the economic crisis.

The officer spoke on condition of anonymity in keeping with police regulations.