PARIS (AP) — In its biggest military funeral in decades, France is honoring 13 soldiers killed when their helicopters collided over Mali while on a mission fighting extremists affiliated with the Islamic State group.

French President Emmanuel Macron and Malian President Ibrahim Boubacar Keita will preside over a somber ceremony Monday at the gold-domed Invalides monument in Paris. The French government invited citizens to pay respects along the route of the funeral cortege.

The 13 coffins, draped in the French tricolor, arrived in France over the weekend.

Tuesday’s crash was France’s highest military death toll since 1983. The French military says it was the result of complex coordination during a combat operation and has dismissed a claim of responsibility by an IS-linked group.

The crash drew global attention to an emerging front for groups affiliated with IS.