French anti-terrorism police arrested four Islamist radicals on Wednesday on suspicion they were planning an imminent attack in central Paris, the localTF1 television said.

Three men and one women were arrested at dawn in Paris and the nearby northern suburb of Seine-Saint-Denis. Security forces had files on four of them for their Islamist ties, TF1 said on its website.

Police also seized an unused cartridge for an automatic rifle and computer equipment, TF1 said.

Prosecutors were not immediately available for comment. Police had no immediate comment.