Lagos, Nigeria (CNN) -- The death toll from weekend violence in central Nigeria climbed to more than 200 Monday after members of a machete-wielding Muslim group attacked mostly Christian villages, officials said.
More than 200 were dead and 32 injured, according to Choji Gyang, a religious affairs adviser to the head of Plateau state, who said bodies were still being recovered. Sani Shehu, president of the non-governmental agency Civil Rights Congress, put the number of dead at about 485 people.
Twenty-six arrests had been made in connection with the violence, Gyang said.
Nigerian Vice President Goodluck Jonathan put security on high alert Sunday and began operations to capture the "roving bands of killers" who attacked the town of Dogo Nahauwa, just south of Jos.
The townsfolk are predominantly Berom, an ethnic group that mostly practices Christianity, said Manase Pampe, Red Cross spokesman for its Plateau state office. Reports of the attack described the assailants as members of the Muslim Hausa-Fulani ethnic group, Pampe and government spokesman Gregory Yenlong said.
The attackers stormed the town at 3 a.m. Sunday (9 p.m. Saturday ET) and remained there for 2.5 hours, Pampe said. Buildings were set afire and people were attacked with machetes, Yenlong said.
The violence resembled previous outbreaks of ethno-religious clashes in the west African nation.
The Plateau state attack prompted Jonathan to place the area and neighboring states on "red alert," his office said in a news release. He directed security forces to "undertake strategic initiatives to confront and defeat these roving bands of killers," the release said.
Jonathan, who was installed as acting head of state in February while President Umaru Yar'Adua recovers from illness, called for calm.
"He calls on all Nigerians to remain peaceful and law abiding, since violence only begets further violence," the release said. "He also sympathizes with those who have lost relatives and friends in these attacks, asking the Almighty to grant them the fortitude to bear the loss."
Hundreds fled the town as the violence raged Sunday. The Red Cross was caring for about 600 people at its camp in Boto in Bauchi state, said Alhaji Abubakar, the group's spokesman in the state. Bauchi is just north of Plateau state.
Forty-eight people were treated at hospitals, national Red Cross spokesman Umar Maigari said. Red Cross officials had counted 30 bodies in one community, but were unable to continue their investigation, he said. Residents wanted to direct the attention to burying the dead, he said.
The most populous country in Africa, with a population of more than 150 million, Nigeria is almost evenly divided between Muslims and Christians.
With more than 78 million Muslims, it has the sixth-largest Islamic population in the world, according to a study last year by the Pew Forum on Religion and Public Life.
While some outbursts of violence are between Christians and Muslims, some disputes are also ethnic-based. The country is home to 250 to 400 ethnic groups, making it one of the most diverse African nations, according to the International Displacement Monitoring Centre.
Thousands were displaced in January when violence flared up in Jos, Shehu said in January. A local activist said 69 people had been killed and about 600 injured.
Also in January, at least 150 Muslims were killed during an attack on the town of Kuru Karama, south of Jos, Human Rights Watch reported. Community leaders from Jos and journalists told Human Rights Watch that they saw dozens of bodies lodged in wells or sewage pits. Most of the town's homes were burned, the group said.
In November 2008, at least 700 Nigerians died in Christian-Muslim riots that followed a disputed local election, Human Rights Watch reported.
CNN's Christian Purefoy contributed to this report.