At least 71 people including 12 members of the security forces were killed in northern Rakhine State in Myanmar on Friday after insurgents attacked a series of police posts and an army base.
Army sources estimate that around 1,000 insurgents were involved in this offensive, five times more than were involved in similar attacks in October 2016.
The Arakan Rohingya Salvation Army (ARSA), which staged October's attacks, claimed responsibility for Friday morning's offensive and warned of more attacks to come.
The army said militants used sticks and swords and destroyed bridges with explosives.
The situation in Rakhine deteriorated early in October when security forces began a new “clearance operation” in a remote mountain area.
The leader of ARSA, Ata Ullah, has said hundreds of young Rohingya have joined the group, which claims to be waging a legitimate defense against the army and for human rights.
Over the last several months the government has accused the insurgents of instigating a campaign of terror against village chiefs and killing government informers, disrupting government information networks.
(With input from Reuters)