As many as 500 people may have been killed in attacks on two predominantly Christian villages near the Nigerian city of Jos.

The worst hit was the village of Dogo Nahawa, where Muslims reportedly set fire to homes before killing villagers as they attempted to flee.

Officials raised the number of dead from their previous estimate of around 100. They said the attackers had been armed with machetes.

One reporter with the independent Nigerian news network Channels counted more than 200 bodies, mainly women and children, according to The Guardian. Some of the bodies had machete wounds while others were charred.

Locals believe the attacks were carried out in revenge for the killing of hundreds of Muslims in January. The area has been blighted for years by tensions between the Muslim Fulani ethnic group and the Christian Berom ethnic group.

Christian Solidarity Worldwide's Chief Executive Mervyn Thomas called on the authorities to bring the perpetrators to justice.

"Innocent men women, children and even babies have been murdered in a most appalling manner simply because of their religious affiliation," he said.

"What is particularly worrying is that attacks continue to occur despite a curfew that the army is meant to be enforcing. The army must begin to conduct stringent searches of all vehicles travelling outside curfew hours in order to restore its credibility with the local population.

"Urgent action must also be taken to track down both the perpetrators and organisers of this massacre and to bring them to justice."

Peter Gyang, who lost his wife and two children in the attacks, was quoted by Agence France Presse as saying: “Gunshots were fired just to scare people out of their houses only to be machete as they fled into the bush.

“The operation started around 3:00am (0200 GMT) and lasted till 6:00am and there were gunshots, but we did not see a single policeman.

“We no longer have confidence in the security agencies.”

Acting President Goodluck Jonathan has placed security forces in Plateau State and neighbouring states on high alert in a bid to stop the violence spreading.