PARIS/LONDON (Dispatches) -- Four people were stabbed on Friday near the former offices of the Charlie Hebdo satirical magazine in Paris that was attacked by militants over five years ago, Prime Minister Jean Castex said, and police said a suspect had been arrested.
A police source had earlier told Reuters that two of the four wounded had life-threatening injuries.
Paris police said one person had been arrested near the Bastille opera house.
One police source said a machete had been found at the scene. Another police sources said a meat cleaver had been found there.
Local authorities asked people to avoid the area and said a police operation was under way in a northeastern district of Paris. Deputy mayor Emmanuel Gregoire tweeted that police were hunting a "potentially dangerous” individual.
The Paris metro closed lines in the area.
Fourteen people went on trial in Paris on Sep 2, accused of being accomplices in the attack on the Charlie Hebdo offices in January 2015 that killed 12 people.
In Britain, a police officer was shot dead in the early hours of Friday by a man who was being held at a custody centre in south London.
Police said the incident occurred at about 2.15 a.m. while the man was being detained at the Croydon Custody Center where arrested suspects are processed. The unnamed officer was treated at the scene and taken to hospital where he died.
A 23-year-old man was detained at the scene of the shooting and was taken to hospital having also suffered a gunshot wound. He is in a critical condition.
Officers did not open fire and the BBC said it was believed the man had turned the gun on himself. A murder investigation is underway, police added.
The shooting of officers is very rare in Britain where the vast majority of police remain routinely unarmed. A 2017 survey found just over a third wanted to carry weapons routinely, but 43% did not.
The last officers to be shot dead while on duty were unarmed police constables Fiona Bone, 32, and Nicola Hughes, 23, who were gunned down by a fugitive in 2012 after responding to a hoax call about a burglary in the northern English city of Manchester.