This story has been updated.

Update, Saturday, 6:11 p.m. EDT: Militants described by witnesses as members of Boko Haram have killed 39 people in the country's northeast Saturday, following a brutal attack Friday night in which the group is said to have beheaded 23 people. According to the Associated Press, 25 people were killed Saturday, as voting began in Nigeria's nationwide election, when the militants torched their houses and shot them as they tried to escape. The death toll included a legislator from the opposition All Progressives Congress party, Umaru Ali, AP reported. All the attacks took place in areas where the military said Friday it had cleared out Islamic extremists. Forteen other people were also killed in separate attacks on the towns of Biri and Dukku.

Original story:

Purported members of the Islamist militant group Boko Haram beheaded 23 people and torched homes late Friday in the northeastern Nigerian town of Buratai, a federal official confirmed. The attacks occurred just hours before polls opened for Nigeria’s general elections.

"There was an attack on Buratai late Friday by gunmen suspected to be insurgents. ... They beheaded 23 people and set homes on fire," Mohammed Adamu, a federal lawmaker who represents Buratai, told Agence France-Presse. “At least half the village has been burned.”

An unnamed nurse who treated injured villagers at a hospital in nearby Biu said they confirmed the militants had beheaded several people. No one has claimed responsibility for the attack as of yet, but the targeting of unarmed civilians was consistent with Boko Haram’s past methods in the region.

There was no clear indication if the attack was meant to coincide with the start of Nigeria’s elections. But Boko Haram leader Abubakar Shekau said the group planned to target voters who turned out for Saturday’s polls.

At least eight people were killed in a separate attack Saturday in Gombe, also located in northeast Nigeria. An assembly candidate for the opposition All Progressives Congress (APC) was among the dead, Reuters reported. Bystanders said the gunmen declared the attack was meant to disrupt voting, AFP noted. A total of 15 people have been killed Saturday in attacks near polling stations.

President Goodluck Jonathan of the People's Democratic Party faces opposition candidate Muhammadu Buhari in what is expected to be Nigeria’s tightest presidential race since military rule ended in 1998. Nigeria’s Independent National Electoral Commission (INEC) announced Saturday that voting would carry over into Sunday in some regions because of voter accreditation issues.

Polls were initially slated to open Feb. 14, but the election was delayed amid concerns about voter identification and Boko Haram activity. More than 1,000 people were killed in post-election violence in 2011.