Spanish police arrested three people on Saturday for suspected links to the armed Basque separatist (search) group ETA, officials said.

The three arrests brought to 18 the number of ETA (search) suspects detained this week as part of a crackdown on the armed group's recruitment network.

ETA is blamed for a car bomb attack in Madrid on Wednesday that injured 43 people near a convention center where Spanish King Juan Carlos (search) and Mexican President Vicente Fox were to inaugurate an art fair.

The suspects were arrested in Madrid, in the northern Basque town of Basauri, and in Campello in the Mediterranean province of Alicante, police said.

In Madrid, police arrestedent Basque homeland in land straddling northern Spain and southwest France.