JOS, Nigeria-- Hundreds of people, including many women and children, were killed in ethnic violence near the city of Jos in Nigeria, officials say.

They said villages had been attacked by men with machetes who came from nearby hills.

Troops have now been deployed in the area and dozens of arrests are said to have been made.

Acting President Goodluck Jonathan has ordered security forces to prevent more weapons being brought into the area.

Jos has been under a military curfew since January when at least 200 people died in clashes between Christians and Muslims.

The latest attacks are said to have been reprisals for the January killings.

"We have been able to make 95 arrests but at the same time over 500 people have been killed in this heinous act," Dan Manjang, an adviser to the Christian-dominated Plateau state government, said.

Many of the dead in the villages of Zot and Dogo-Nahawa are reported to be women and children.

Mark Lipdo, from the Christian charity Stefanos Foundation, said Zot village had been almost wiped out.

He said: "We saw mainly those who are helpless, like small children and then the older men, who cannot run, these were the ones that were slaughtered."

A resident of Dogo-Nahawa said that the attackers had fired guns as they entered the village before dawn on Sunday in defiance of a curfew.

"The shooting was just meant to bring people from their houses and then when people came out they started cutting them with machetes," Peter Jang said.

Some witnesses said villagers were caught in fishing nets and animal traps as they tried to escape and were then hacked to death. Mud huts were also set on fire.