PARIS • French anti-terrorism police arrested a group with Islamist militant ties, suspecting one of them may have been planning an attack in Paris, said France's Interior Minister Bernard Cazeneuve.

"We have information about one person that suggests that he could undertake violent actions in France," said Mr Cazeneuve, adding that the man was thought to have ties with the Islamic State in Iraq and Syria (ISIS).

"This person was arrested this morning along with people linked with him," Mr Cazeneuve said on Wednesday, warning against jumping to the conclusion that an attack was imminent.

Earlier TF1 television reported that three men and one woman were arrested in Paris and the nearby northern suburb of Seine-Saint- Denis on the suspicion that they were planning an imminent attack.

"This is an extremely sensitive time. We have got information on people, they are preparing things, they are looking for a target, they are in France and near France," a source close to President Francois Hollande said.

During the arrests on Wednesday, police seized an unused cartridge for an automatic rifle and computer equipment, TF1 said on its website. No weapons were found, a source close to the investigation told Reuters.

The investigation was focused in particular on a 28-year-old Frenchman who had been under house arrest since Feb 29 under a state of alert that has been in effect in France since Islamist militants killed 130 people in a series of attacks last November.

The man was sentenced to five years in prison in March 2014 after he was arrested two years earlier when he tried to leave France for Syria. He was released in October last year, TF1 reported. His partner was also arrested, along with two French brothers of Turkish origin.

On Tuesday, Belgian police shot dead a 35-year-old Algerian during a raid on a Brussels apartment in the hunt for clues to the attacks in Paris last November.

The man who was killed, Mohamed Belkaid, had potential links to radical Islam, Belgian prosecutors said on Wednesday. Two other suspects from the counter-terrorism raid, which left four police officers wounded, remain on the run, added the prosecutors.

Belkaid was in Belgium illegally. In the apartment where he died, police found an ISIS flag, 11 cartridge clips and numerous shell casings. It was unclear whether he had any connection to November's attacks.

The French and Belgian authorities have detained nearly a dozen men suspected of helping the Paris attackers either before or after the Nov 13 assaults, but are still seeking others.

The chief fugitive is Salah Abdeslam, 26, a French citizen who is believed to have participated in the Paris attacks. Abdeslam, who was born in Brussels to parents who had emigrated from Morocco, fled to Belgium immediately after the attacks.

REUTERS, NEW YORK TIMES