N'Djamena (AFP) - Seventy-one Chadian soldiers have been killed and 416 wounded in less than three months of fighting in the regional campaign to crush the Boko Haram insurgency, Chad's army said Friday.

Chad has sent about 5,000 troops to fight alongside soldiers from Nigeria, Niger and Cameroon against the Islamist radicals whose Nigeria-based insurgency has increasingly spilled over into neighbouring nations.

The regional fightback, concentrated in border areas south of Lake Chad and in northeast Nigeria, seems to have stopped the militants' advance for now.

Chad army chief General Brahim Seid told reporters in his country's capital N'Djamena the "valiant soldiers" had died since February 3 in the "just and noble cause of bringing peace and security" to the region.

"They (troops) have liberated 11 communities in Cameroon, Niger and Nigeria from the hands of Boko Haram," said Seid. "Chadian forces will continue to hunt the terrorists of Boko Haram wherever they are found."

The stepped-up efforts against Boko Haram came after the Nigerian army was repeatedly criticised as ill-equipped and ineffective against the jihadists.

Nigeria's military -- with major backing from its neighbours -- has since claimed huge victories over Boko Haram in the northeast, retaking a series of towns and villages previously under rebel control over the last two months.

Nigerian President Goodluck Jonathan's inability to get a hold on the insurgency that has killed some 13,000 people and sent 1.5 million fleeing their homes was a factor in his defeat at elections last month.

Nigeria's president-elect Muhammadu Buhari will not take charge of the fight against Boko Haram until late May, but he has vowed to be a more effective commander-in-chief than Jonathan, in part by ensuring that the military is properly funded and equipped.

The UN on Thursday launched an appeal for $174 million (164 million euros) to give "life-saving aid" to the almost 200,000 Nigerians who have fled the country due to the group's brutal attacks.

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After months of the aggressive campaign, regional military leaders believe Boko Haram's military capacity has been significantly weakened.

They regularly claim to have inflicted heavy casualties on Boko Haram, though the numbers are impossible to verify independently.

"That does not mean the threat has completely been averted," Niger army chief Seyni Garba said earlier this month.

He noted that even if Boko Haram is weakened it has the power to carry out "massive assaults", including suicide bomb attacks.

"There are still very small groups in certain communities," Garba said, referring to islands in Lake Chad, where the borders of Chad, Nigeria, Cameroon and Niger converge.

A new attack happened Thursday when gunmen suspected to be Boko Haram Islamists killed two residents in Buratai village in northeast Nigeria.

Two weeks earlier insurgents beheaded 23 people in the same community.