Officials from a Nigerian college near the site of a massacre that left at least 40 people dead this week dismissed reports Thursday that the killings were linked to tensions over a campus vote.

However, claims persisted among residents in the town of Mubi in northeastern Nigeria that the massacre, which saw victims shot or have their throats slit, was somehow linked to student politics.

Suspicions have also fallen on Islamist extremist group Boko Haram, which has carried out scores of attacks in Nigeria's northeast and was the target of a high-profile military raid last week in Mubi.

Nigerian police said they had made many arrests over the massacre, but offered no clues for what prompted it as questions mounted.

"I have no evidence to link it to the election," said Shuaib Aroke, deputy registrar at Federal Polytechnic Mubi, where some of those killed in the massacre overnight Monday to Tuesday were enrolled.

"It is a fallacy," he told AFP of a link to the vote being suggested by some Nigerian authorities. "We are united here at polytechnic," added Aroke, who said he is currently in charge of security on campus.

He however said he had no information on who was behind the killings.

The school's dean of student affairs, Ahmed Baba Karewal, made similar comments, saying claims that the violence was linked to the election do "not correlate at all."

Residents of the area where the massacre occurred described hearing gunshots overnight Monday to Tuesday, before gunmen descended on the area.

"They killed my neighbour Sylvanus," one 27-year-old resident said. "I heard when they kept shouting the name -- 'Sylvanus! Sylvanus!' When he answered and came out, they shot him dead."

In the student vote, there were suggestions of ethnic or regional tensions in a country split between a mainly Muslim north and predominately Christian south. A spokesman for the National Emergency Management Agency has said some of the victims were candidates.

Aroke however said the election went off peacefully and all candidates signed the results sheet.

Police in northeastern Adamawa state, where Mubi is located, said they had arrested "many suspects" in connection with the slaughter, but have declined to provide further details.

Another school official, who requested anonymity, said most of those being held were students. He also said the death toll was at least 40.

Police have given an official death toll of 25, saying at least 22 victims were students, with 19 from the polytechnic and three from another school.

On Wednesday, security forces had gone house to house and blanketed Mubi, a commercial hub and university town located near the border with Cameroon.

Security deployments appeared less intense on Thursday, though there were checkpoints along the road from the state capital Yola to the town and a large deployment of soldiers could be seen after the 3:00 pm to 6:00 am curfew began.

The killings occurred in a student housing area off-campus of Federal Polytechnic Mubi, an ethnically mixed school with several thousand students.

Residents said it seemed the victims were both Muslims and Christians, but police had not commented, as is often the case in Nigeria, where ethnic and religious divisions regularly lead to unrest.

The suggestion that the killings were linked to the student election raised questions over how and why the dispute would have turned so violent.

At the same time, Boko Haram has continually widened its targets and its attacks have become increasingly sophisticated.

Nigerian officials have been seeking to show success in the fight against the extremists with a number of raids and arrests. There had been a lull in major attacks in recent weeks.

The group has been blamed for more than 1,400 deaths since 2010 as part of its insurgency in northern and central Nigeria, Africa's most populous nation and largest oil producer.

Boko Haram has claimed to be seeking an Islamic state in northern Nigeria, but its demands have repeatedly shifted and it is believed to include a number of factions with varying aims.

Imitators and criminal gangs are also believed to have carried out violence under the guise of the group.

Nigerian President Goodluck Jonathan announced Thursday he had named a new chief of defence staff. There was however no indication it was linked to the massacre.