Enough explosive material was found in the house in La Linea where the Turk lived to blow up a bus, and the material could be especially dangerous if combined with shrapnel, Jorge Fernandez Diaz, Spain's interior minister said. (He also said) the suspects had information about remote-controlled airplanes, and some of them "have experience producing explosives and car bombs and training in shooting." The alleged cell members had been mastering the art of flying on motorized paragliders, leading Spanish investigators to believe the group was planning an attack from the air.

"This is one of the most important operations carried out against al-Qaeda," Fernandez Diaz told reporters. He said the operation involved close collaboration with intelligence services from "Spain's allies," without identifying any of the countries.

Spanish authorities had been watching the suspects for "some time," the minister said and decided to arrest them after the Russian and the Russian of Chechen descent took a bus toward France. The two arrested in the bus were traveling from southern Cadiz to the northern town of Irun, possibly intending to cross into France, the minister said. The pair had been in Spain for about two months. Cadiz is near the large US military base in Rota alongside the Mediterranean. "Police moved to arrest them when it became known that they planned to leave Spain," he said.

Fernandez Diaz did not disclose the suspects' names, but said two were suspected al-Qaida operatives while the Turk was a facilitator. Pictures of the suspects were released by Spanish authorities but they were identified only by their initials: C.Y. for the Turk and A.A.A. and M.A. for the other two. The mug shots showed three men who appeared to be in their 30s, two with crew cuts and one with hair down to his shoulders.