Nigerian authorities said on Friday that 66 people were killed by unidentified gunmen in Kajuru area of the northern state of Kaduna on the eve of the country's presidential election.

State government spokesman Samuel Aruwan said in a statement that eight settlements were attacked early Friday, with 22 children and 12 women among the victims.

Aruwan said the cause of the violence was unclear, and some security operatives had been deployed to the affected localities.

Some suspects have been arrested in connection to the violence, he said.

The spokesman urged community, traditional and religious leaders in the area to encourage residents to avoid any reprisal attacks and to leave the matter in the hands of the security and law enforcement agencies.

"The killings are being investigated and residents are assured that indicted persons will be prosecuted," he said.

On Jan. 22, the Nigerian government alleged there were security threats to the upcoming general elections in the country, alerting citizens of the west African country to be wary of pending attacks before, during, and after the polls.

Kaduna, located in the north part of the country, was among states earlier listed by the government as one of the flashpoint areas.