By Emma Farge
DAKAR (Reuters) - Boko Haram has dramatically scaled back attacks in Cameroon in recent months, analysts said on Wednesday, suggesting a regional security force is gaining ground against the militants.
The Islamist movement - which controlled an area the size of Belgium in northeast Nigeria last year and raided Cameroon and other neighbors to expand its "caliphate" - had since suffered a string of defeats, International Crisis Group (ICG) said.
The report came days after security and U.N. sources said hundreds of Boko Haram fighters and their families had surrendered on another frontline in Chad.
There was no comment from any of the factions of Boko Haram which is still seen as one of the main security threats in West Africa.
"We've seen a dizzying downwards spiral in the number of attacks and suicide bombings," said Hans De Marie Heungoup, one of the report's authors.
Two years ago, attacks were happening on an almost daily basis, he said. But the number had fallen to between six and eight a month since September.
"[Boko Haram] has suffered heavy losses and seen its conventional capacities reduced," the study said, partly thanks to last year's formation of a 10,000-strong regional force with troops from Nigeria, Chad, Cameroon, Niger and Benin.
Up to 1,000 fighters with heavy weaponry and armored vehicles joined strikes in Cameroon's Far North Region in 2014-15, the report said.
But attacks were now focused on the northernmost tip of the region where fighters continued to control part of the fishing industry of Lake Chad amid a labyrinth of waterways.
Recruitment is also faltering in Cameroon although forced enlistment remains a risk, ICG said.
Up to 4,000 Cameroonians are thought to have joined the group and some were given sign-on bonuses of up to $2000 and a motorbike, according to the study, citing interviews with locals.
Those who proved their loyalty by killing their parents often enjoyed quick promotion, it added.
Analysts say the faction around the Lake Chad Basin represents the stronger branch of the group, loyal to Islamic State (IS) and led by Abu Musab al-Barnawi. Another faction led by Abubaker Shekau is based further south in Nigeria's Sambisa forest.
(Reporting by Emma Farge; Editing by Nellie Peyton and Andrew Heavens)