Suspected Islamist militants uncovered in a Paris suburb by police were planning an attack on the French capital's La Defense business district, a source close to the investigation and two police sources said on Wednesday.

A woman suicide bomber blew herself up and another militant died when police raided the apartment in the St. Denis suburb as part of the investigation into last week's coordinated bombings and shootings.

"The police forces were looking for terrorists who were preparing another attack on the basis of information from the (local) counter-terrorism services and overseas," said the source close to the investigation.

"This new team was planning an attack on La Defense."

The French interior ministry declined to confirm or deny the information.

Officials said police had been hunting Abdelhamid Abaaoud, a Belgian Islamist militant accused of ordering the Nov. 13 attack, but more than eight hours after the launch of the pre-dawn raid it was still unclear if they had found him.

Seven people were arrested in the operation including three people who were pulled from the apartment, officials said.

"It is impossible to tell you who was arrested. We are in the process of verifying that. Everything will be done to determine who is who," Paris prosecutor Francois Molins said at the end of the operation. - Reuters