French Prime Minister Sébastien Lecornu announced on Friday that one person had been killed and five others injured in a shooting in the town of Trappes, in the Yvelines department.

Lecornu confirmed that authorities had arrested a suspect and said security and judicial authorities had been mobilized to respond to the incident.

Interior Minister Laurent Nuñez stated that three of the injured were in extremely critical condition and described the shooting as a clear act of terrorism.

France’s National Anti-Terrorism Prosecutor’s Office subsequently announced the opening of an investigation into the attack.

Local media reported that a gunman had opened fire on pedestrians from inside a vehicle, although the full circumstances and possible motive remained unclear.