Updated

France has formally opened a terrorism investigation into three French recruits of the Islamic State group calling for attacks back home in a propaganda video.

The three men, who appear under Arabic pseudonyms, appear in a montage that also shows multiple French passports being burned in a campfire. They call on fellow French to join them or carry out attacks in France.

Agnes Thibault-Lecuivre, spokeswoman for the Paris prosecutor's office, said an anti-terrorism investigation was opened on Thursday to identify the men.

A former French fighter linked to IS has been accused in a deadly shooting at a Brussels Jewish museum, and European officials fear that newly radicalized and trained militant recruits will return from the battlefields of Syria and Iraq and launch attacks at home.