Boko Haram is probably the most effective jihadist fighting force in Africa.

(Reuters) – A gunbattle between security forces and Islamist insurgents in Nigeria a week ago killed 228 people, a local senator said on Saturday, putting the death toll six times higher than the government’s estimate.

A large number of civilian deaths will fuel accusations that the military acted heavy-handedly and failed to protect bystanders and might also increase pressure on the government to seek a negotiated settlement with the radical group Boko Haram.

There have been conflicting death tolls from the April 19 operation carried out by joint forces from Nigeria, Chad and Niger against Boko Haram insurgents in the remote northeastern town of Baga.

The Red Cross is investigating a report by locals that 187 people died, including many civilians, but defense spokesman Chris Olukolade said only 37 were killed.

The military barred aid agencies from entering Baga for several days after the attack. The Red Cross and some other agencies have since been given access but none has issued a definitive death toll.