US military chief General Martin Dempsey said Thursday that American advisers must be sent to Iraq’s western Anbar province to counter Islamic State jihadists, but the Baghdad government must first arm local Sunni tribes.

Due to recent IS gains, “we need to expand the train, advise and assist mission into al-Anbar province, but the precondition for that is that the government of Iraq is willing to arm the tribes,” Dempsey told a news conference.