Spanish police have arrested two people in Spain's North African enclave of Ceuta accused of connections with Islamic militants, the Interior Ministry said on Friday.

The two detained had been through a long radicalization process and formed part of a group which was thought to be at an advanced stage of preparation for potential attacks, it said.

Police were searching six locations in relation to the arrests, the ministry said.

Spanish police have arrested 180 people accused of connections to Islamic militants since raising the country-wide security alert to one below the highest level in 2015.