The militant Islamist group Boko Haram has given Christians three days to leave northern Nigeria following attacks on churches and other targets over Christmas that left more than 40 people dead.
The ultimatum, issued late on December 31, intensifies the threat to Christians in the Muslim-majority North, parts of which are under a state of emergency after the Christmas violence.
Boko Haram, which wants to impose sharia law across the country, claimed responsibility for a coordinated series of bomb and gun attacks on churches and the security services in five states on Christmas Day 2011.
The majority of the fatalities occurred at a Catholic church in Madalla, near the capital, Abuja; around 35 worshippers were killed as explosives were hurled at the congregation as they left the Mass.
It is the second consecutive year that Boko Haram has staged Christmas attacks; last year, 32 people were killed in a series of bombings in Jos on Christmas Eve.
Barnabas Fund warned just before Christmas that the festive season might see anti-Christian attacks in various parts of the world. Nigeria is just one of several countries where such violence broke out. In Uganda, Umar Mulinde - a Christian convert from Islam - was assaulted on Christmas Eve. Assailants spewed acid on the Christian pastor, blinding one eye and yielding severe burns. He has been an outspoken opponent of introducing Islamic religious law, known as sharia, to Uganda's courts.