MADRID Spain's High Court is investigating Catalan nationalists for setting fire to a photograph of King Juan Carlos, the government said on Friday.
Public prosecutors have requested information from regional authorities about Thursday's incident, in which masked Catalan nationalists used flaming torches to set the picture of the king in military uniform alight.
"I wish to express our full and absolute condemnation of the incidents," Deputy Prime Minister Maria Teresa Fernandez de la Vega told reporters.
Images of the youths, who chanted anti-monarchist slogans as the king was visiting a technology park in the town of Gerona, were given wide play by Spanish media.
If found guilty of insulting the monarchy, suspects could face from six months to two years in prison.
Juan Carlos is widely considered to one of the architects of Spanish democracy by his contribution to stopping an attempted right-wing coup by military forces in the early 1980s.
Spain's conservative opposition Popular Party blamed Socialist Prime Minister Jose Luis Rodriguez Zapatero, saying he has put Spanish unity in danger by kow-towing to nationalist sentiment.
Debate has raged in the northern Basque region, long troubled by separatist violence, over whether to call a referendum on independence from Spain.
Similar nationalist sentiment, though largely non-violent, exists in Catalonia.