Authorities in Nigeria have been accused of failing to protect the people following deadly violence at the weekend.
At least 100 people are reported to have been killed in attacks by militant Islamist group Boko Haram on the towns of Damaturu, Maiduguri and Patiskum in the north of the country. At least nine churches were attacked in Damaturu.
Bishop Oliver Dashe Doeme of Maiduguri told Aid to the Church in Need that the government in north-east Nigeria had "let the people down" by failing to prevent the attacks and protect people.
He said priests had been forced to run for their lives as militants attacked St Mary's Catholic Church.
"The church was completely burnt to ashes," he said. "It was one of the biggest churches in the diocese."
Bishop Doeme said politicians in the area were using Islamist groups for their own interests.
"Religion is a very sensitive issue and the politicians can whip up hatred and suspicion very easily," he said.
He appealed to the Nigerian government to shore up security, saying that it would require a "concerted effort" to restore law and order.
"If security had come earlier, this wouldn't have happened. The police have let the people down."
According to Human Rights Watch, last weekend's attacks saw the highest number of deaths in a single day since Boko Haram began its campaign of violence in Nigeria in July 2009.
Release International fears Christians will continue to be "prime targets" of Boko Haram as it seeks to impose strict Islamic law in Nigeria.
"Boko Haram seems to be bent on destabilising the nation to pave the way for an Islamist state – and at the forefront of their attacks are churches," he said.
Although police stations and government buildings were attacked, Release said churches accounted for more of the targets.
It said militants were trying to drive out non-Muslims from the area and would not stop until the "harshest" form of Islamic law had been established in Nigeria.
"The government must take effective action to prevent religious cleansing and to safeguard the Christian community," he said.
Barnabas Fund has launched an appeal to provide practical support to Christians displaced by the violence and congregations that have lost their churches.
The International Director of Barnabas Fund, Dr Patrick Sookhdeo, urged Christians to pray for the situation.
"Islamists have once again wreaked havoc in Nigeria, leaving a trail of devastation and destroyed lives," he said.
"Amid this ongoing carnage, our brothers and sisters continue to suffer.
"We must pray earnestly for peace in that troubled land and be ready to help meet the practical needs of Christians who have been affected by the violence."
Human Rights Watch has condemned the violence as an "indefensible attack on human life". It is calling upon the authorities to act swiftly in bringing the perpetrators to justice.
To donate to the Barnabas Fund appeal, go to: barnabasfund.org/donations/?id=00-345&appealCode=NIG%2011/11