According to human rights group Amnesty International (AI) report, released on Wednesday, at least 1,600 people have been killed by Boko Haram and death toll have reached up to 3,500 this year alone.
Attacks and the deaths have taken place in Nigeria, Cameroon, Chad and Niger where militant group keeps remaining a deadly threat despite military progress, AI stated at the report.
"The number of people killed so far this year is truly shocking with more than 3,500 civilian fatalities in less than 300 days," said Amnesty's Africa director for research and advocacy, Netsanet Belay.
"Governments in the affected countries must take all necessary legal measures to ensure the security of civilians in troubled areas," he added.
Most of the attacks took place in Borno State and militants chose to bomb or suicide attacks in places such as markets, bus stations and houses of worship.
On the other hand, Nigerian military claimed that they managed many things like shattering militants’ camps, capturing alleged leaders of the militants and saving many women and children kidnapped by the group.
Amnesty International did not mention about exact toll of deaths for per country but AFP reported that at least 1,260 civilians have been killed since PM Muhammadu Buhari came to power on May 29 promising to destroy Boko Haram.
Nearly 140 people were killed in bombing conducted by Boko Haram in Borno State on September 20.
Army spokesman Colonel Tukur Gusau said that the militants poisoned water hole and streams in some places they had captured before.
Boko Haram also drawn strong international criticisms right after its fighters kidnapped 276 female students in April 2014. The girls abducted from the Government Secondary School, in the Nigerian town of Chibok are still missing, however 57 managed to escape.
Upon kidnapping, a youth march was organised on August 27 by relatives of more than 200 school girls kidnapped by Boko Haram in April last year, to draw attention that it has been over 500 days since the girls disapeared.
Boko Haram is a Nigerian based militant group established in 2002 who carry out their operations in West African countries including Chad, Niger and Cameroon.