(CNN) -- Three suspected terrorists have been arrested in southern Spain in "one of the biggest operations against al Qaeda in Spain," Spanish Interior Minister Jorge Fernandez Diaz said Thursday.
Two of the group members were arrested Wednesday and the third Thursday, he said.
The Interior Ministry said the men were "ready to act in Spain and Europe." One of the men is Turkish, and the other two are believed to be of Russian-Chechen origin. They were detained in Cadiz and Almuradiel -- 260 miles away -- and had gathered enough explosives to "blow up a bus," according to police sources. Two of them were on a bus traveling to France when they were apprehended, and Diaz said they "resisted fiercely." The third was held in Cadiz.
The investigation is in its early stages, but Spanish security services say they believe the men may have been plotting to attack the nearby joint U.S.-Spanish naval base at Rota near Cadiz or British interests in Gibraltar, according to Fernando Reinares, a senior international terrorism analyst at The Elcano Royal Institute in Madrid who was briefed by Spanish security services on the investigation.
Spanish police are still searching for explosives in San Roque, Cadiz, where they suspect the men had stored bombs and documents. Wiretaps indicate that the Turkish citizen's wife had "removed evidence from the house" before the arrest. They are also analyzing the computers and files on a laptop that belonged to one of the arrested men.
Spanish security services suspect the alleged terrorist cell of ties to the Pakistani terror group Lashkar-e-Tayyiba, Reinares told CNN, and they believe one or more of the trio received terrorist training in Afghanistan and Pakistan.
The alleged cell was first detected in Spain around a month ago but had been previously tracked by other Western intelligence agencies, according to the Spanish Interior Ministry.
Spain's interior minister 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, according to Reinares.
Reinares said the alleged terrorist cell's operation was different from other recent terrorist plots in Spain that were the work of "self-starting, self-radicaling" Islamist militants. He said Spanish investigators believe this cell was dispatched from overseas to carry out a terrorist attack. While the main hypothesis is they were plotting to hit American or British targets, Spanish investigators have not ruled out the possibility that the men were planning to launch an attack on mainland Spain or elsewhere in Europe, he said.
Reinares said this was not the first alleged terrorist cell linked to Lashkar-e-Tayyiba to be arrested in Spain. A group linked to a militant with ties to Lashkar-e-Tayyiba who had trained in Kashmir was arrested in Barcelona in 2004.
Indian and Western intelligence officials suspect that Lashkar-e-Tayyiba is responsible for the 2008 Mumbai, India, terrorist attacks and that it has established closer ties with al Qaeda in recent years. One of its members was David Headley, a U.S. citizen of Pakistani descent, who was convicted of helping to plan the Mumbai attacks and plotting to attack a Danish newspaper that had published cartoons of the Prophet Mohammed. According to court documents Lashkar-e-Tayyiba commissioned Headley to research targeting the newspaper, but the group never went through with the plot.
A jihadist website associated with al Qaeda posted a request earlier this year asking for "lone wolves living among the enemy" who could speak Spanish, a request that Spanish police interpret as a call for suicide bombers.