President Trump sent his condolences to the French people Thursday after a possible terror attack in Paris, calling it a “terrible thing” and warning that the world has to be strong and vigilant in the face of the terror threat.

“It looks like another terrorist attack and what can you say? It just never ends,” Trump said.

Trump made the remarks during a joint news conference with Italian Prime Minister Paolo Gentiloni, who also sent his condolences to France.

One police officer was killed and two were injured when a gunman opened fire on the famed Champs-Élysées shopping district in Paris, French officials said. Officials said the police officers were specifically targeted.

While noting that he had only just seen coverage of the still-developing event before entering the press conference, Trump said it was a “very terrible thing that’s going on in the world today.”

“We have to be strong and we have to be vigilant and I’ve been saying this for a very long time,” he added.