Barcelona  - The Barcelona home of Infanta Cristina, younger daughter of Spain's King Juan Carlos, had a Molotov cocktail thrown at it by a lone attacker during the night, police said Saturday.

The attack caused only limited damage, and the 43-year-old princess, her husband and their four children were not there.

Police arrested the suspected arsonist Saturday evening. There were no immediate details about his identity or the motive behind the attack.

Media suspect that radical Catalan separatists, who view the Spanish royal family as occupiers, were responsible for the attack.

As recently as Thursday - Catalan national day - masked youths burned Spanish flags and pictures of the royal family in the city.

Cristina and her family moved into the 2,000-square-metre property in the wealthy neighbourhood of Pedralbes three years ago.

The infanta, who works for a private foundation, is married to the professional handball player Inaki Urdangarin, 40.

The couple have three sons and one daughter. (dpa)