Spanish police found material for making explosives and bombs in raids on Saturday in Barcelona, which also led to the arrests of 14 people in connection with a suspected radical Islamist terror network, Interior Minister Alfredo Perez Rubalcaba said.
"During our searches, we found various materials which could be explosives or be used to make explosives," Rubalcaba told a press conference in Madrid.
He also said that the network that could be characterised as "radical Islamist" was "highly organised".
Civil Guard officers made the arrests in the northern port city of Barcelona as part of raids planned with the National Intelligence Center, the Spanish equivalent of the CIA, the ministry said in a statement.
Authorities did not rule out more arrests, the ministry said. Officials gave no further information, but newspaper El Pais said on its website that officers searched a mosque, several homes and an unofficial prayer site.
Most of those detained were believed to be Pakistanis, Europa Press Agency said.