At least one person was killed in an apartment targeted by a police raid Wednesday in the northern Paris suburb of Saint-Denis following the bloody attacks on Paris, according to a source close to the operation.

The source did not identify the casualty. Earlier, a source said the operation aimed at the suspected mastermind of the attacks, Belgian Abdelhamid Abaaoud, and police had been wounded in the shootout.

Police said earlier between two and four people were holed up in the apartment.

Abdelhamid Abaaoud, 27, initially thought to have pulled the strings from Syria, was believed to be among a group of people holed up in an apartment in the northern suburb near the national soccer stadium, which was one of the sites attacked by suicide bombers last week, the source said.

‘The operation is still under way. It’s not over,’ local member of parliament Mathieu Hanotin said on France Inter radio. ‘Everyone must stay indoors. There are still gunmen holed up in the apartment.’

The area is home to the Stade de France, one of several places hit by gunmen and suicide bombers on Friday in the worst ever attack on French soil, which was claimed by the Islamic State jihadist group.

The coordinated assaults killed 129 people and injured more than 350, some of them critically.