British police have arrested seven suspects in Birmingham, in what officials are describing as a major counter-terrorism operation targeting Islamic extremists.

A police statement Monday said six men and a woman were taken into custody. The men were held on suspicion of preparing an act of terrorism, while the woman was arrested for failing to disclose information to prevent an act of terrorism. The suspects, all British residents, range in age from 22 to 32 years old.

Authorities say that because the plot was in its early stages, they were not aware of the targets or what acts of terrorism were being planned. The suspects are being held for more questioning while police continue searching properties across the Birmingham region.

Police say the raid had no connection to an annual conference of the Liberal Democrat party taking place in Birmingham.