Spain's Interior Ministry says police arrested four suspected jihadists in the north African enclave of Ceuta who allegedly formed a cell.
A statement said the arrests were made early Saturday and investigators were assessing the cell's "infrastructure to carry out terror attacks."
Two houses in Ceuta were searched in morning raids on instructions given by a judge and the state prosecutor attached to Spain's National Court.
Spain and Morocco have arrested dozens of suspected jihadist militants and recruiters in recent years, especially around Melilla and Ceuta, both cities that are on the Mediterranean coast and surrounded by Morocco.
The identities of those arrested were not immediately available and the statement said the investigation was ongoing.