PARIS (AP) — French President Emmanuel Macron says France will reconsider the conditions of its military operation in West and Central Africa, after a helicopter collision killed 13 soldiers fighting Islamic State group-linked extremists.

Macron told reporters Thursday that “our mission there is important, yet what we are now living in the Sahel leads us to look into all strategic options.”

He said the French government and armed forces will work on the issue in the coming weeks.

The Monday night crash led to France’s highest military death toll in nearly four decades.

Macron this week defended France’s largest overseas military mission, which involves 4,500 troops, saying it is aimed at enhancing France’s own security and providing support to African countries.

A national tribute ceremony will take place Monday in Paris.