At least 36 people have been killed in a suspected rebel attack in the eastern Democratic Republic of the Congo's Beni region, where hundreds have died in violence since November, a local official has said. DRC troops have been carrying out a military operation on an armed group in the east of the country - long plagued by various armed groups - and fighters have responded with a series of massacres against the civilians. "They were all hacked to death. This brings [the toll] to 36 bodies," local Beni governor Donat Kibwana told the AFP news agency on Wednesday, updating casualties from Tuesday's attack. Officials had earlier reported 15 fatalities. Two people with skull fractures caused by machetes have been admitted to a hospital in Oicha for surgery, AFP said. The main attack took place late on Tuesday in Manzingi, a village 20 kilometres (12 miles) northwest of Oicha, while a pastor was also killed in nearby Eringeti. According to a toll compiled by a civil society organisation, the Kivu Security Tracker (KST), 265 people have been killed in the Beni region since the army began its crackdown on the armed group, the Allied Democratic Forces (ADF), on October 30. The massacres seem to be a tactic by the ADF to frighten the population into silence, local commentators said. The group has also disrupted operations to curb an outbreak of Ebola in North Kivu province. Tuesday's massacre occurred to the west of the ADF's usual area of operations, which is closer to the Ugandan border. The army offensive, unfolding in thick forests, has led to what the military said is the capture of the group's headquarters and the killing of five of its six leaders. The ADF, blamed for the deaths of more than a thousand civilians in Beni since October 2014, began as a rebel group in Uganda that opposed Ugandan President Yoweri Museveni. It fell back into eastern DRC in 1995 during the Congo Wars and appears to have halted raids inside Uganda. Its recruits today are people of various nationalities. United Nations' experts estimated the ADF in 2018 to number around 450 fighters. The spate of massacres has become a major challenge for President Felix Tshisekedi, who took office a year ago. In November, angry protests erupted in the city of Beni, the region's administrative hub, as citizens accused the UN peacekeeping force in DRC of failing to protect them. Tshisekedi, in his first state-of-the-nation address to Congress, last month said he had changed the army command in Beni and sent 22,000 troops to the region.