PALMA DE MALLORCA, Spain (AP) _ Police arrested three armed Basque separatists plotting to assassinate King Juan Carlos on the Mediterranean island of Mallorca, authorities said Thursday.

The three arrested late Wednesday, including a father and son, were found with two machine guns, a rifle with telescopic sighting equipment, several pistols and explosives.

The three men, all members of the Basque separatist group ETA, had rented an apartment near the king's summer residence on Mallorca and overlooking the marina where the royal yacht was moored, said National Police Chief Angel Olivares.

Police arrested 14 more people Thursday in France's southwestern Basque region and another in the Spanish Basque city of San Sebastian in connection with the Mallorca plot, said Interior and Justice Minister Juan Belloch.

Belloch said the king was the main target of the planned attack on Mallorca, with other members of the royal family also possible targets.

ETA has killed 750 people, mostly security force members, since it began a campaign in 1968 for the independence of northern Spain's three Basque provinces. ETA is a Basque-language acronym for Basque Homeland and Freedom.

On a tip-off from French police, Spanish authorities had been following the three since their arrival by boat in Mallorca on July 17 from the French port of Nice.

A palace spokeswoman in Madrid said the king, who has been in Mallorca with Queen Sofia and other members of the royal family since mid-July, had been informed of the operation.

An Interior Ministry spokesman said the three arrested in Mallorca were flown to Madrid early Thursday for questioning.

One of the three was Juan Jose Rego Vidal, who has been arrested several times in the past in both Spain and France. News reports said he was jailed in 1979 for planning an attack on the king and then-Prime Minister Adolfo Suarez.

The other two arrested included Rego Vidal's son, Inaki, and Jorge Garcia Sertucha. French police said the wife and daughter of Rego Vidal were among those arrested in France's Basque region.