Nigeria's police in southeast state of Enugu on Thursday said it had increased surveillance on viewing centers across the state, following the start of the Brazil 2014 World Cup.

The increased surveillance was to discourage any acts of terrorism or violence that might erupt in the course of the Mundial, Ebere Amaraizu, the state police spokesperson told reporters in Enugu, the capital city.

Amaraizu noted that the security challenges in the country had made it necessary to partner with operators of viewing centers, to ensure the safety of football fans.

The police image maker said the issue of security of such centers was not the exclusive preserve of the operators and the police.

"Even the fans should be at alert to determine the type of people sitting close to them," he added.

"We have already stationed our patrol teams in some strategic locations with a view to counter and discourage any act of violence," Amaraizu said.

Early this month, the West African country's military authority had advised fans and owners of viewing centers in the country to be vigilant during the World Cup football tournament.

National defense spokesperson Chris Olukolade gave the advice at a regular news conference in Abuja, the country's capital city, urging fans and citizens to always take notice of strange persons or objects around them.

The advice came barely 24 hours after an explosion hit a bar in Mubi, northeast Adamawa State, where 18 people died while 19 sustained injuries in the explosion.

He also advised them to report strange objects to security agencies for prompt action to forestall untoward incidents.