Christians from different churches, denominations, backgrounds and cultures joined together in unity last night with one purpose – to pray for the kidnapped Nigerian girls and for peace in the nation.

Last month more than 200 girls were abducted in Chibok, northern Nigeria, and recent video footage suggests they have been forced to convert to Islam. Their captors are Boko Haram, the Islamist extremist group that is spreading terror among Christian communities in northern Nigeria.

The mass prayer vigil was held at the Emmanuel Centre in Westminster last night, organised by the National Day of Prayer, the International Strategic Alliance Committee, the Overseas Fellowship of Nigerian Christians and Christian Concern. Representatives from denominations including the Methodists and Anglicans joined them, with the Bishop of Guildford (representing Archbishop of Canterbury Justin Welby) saying: "We know prayer changes things."

The importance of putting aside denominational divides and joining together in unity to pray was emphasised by Ade Omooba, director of Christian Concern, who said: "When people's churches are burnt down they realise that denominations count for nothing. They meet wherever there is a building – Christ is what unites us. The Chibok girls do not care about denomination."

While this kidnapping has brought Boko Haram to the world's attention, the violence and targeting of Christians is nothing new. In January and February 2014 Boko Haram abducted 25 women and girls, and since Chibok they have abducted eight more in Borno, aged 12 to 15. It is estimated that 14,000 Nigerians have been killed in violence since 1999, with more than 100 killed in a predominantly Christian village in Borno state in February of this year. Boko Haram's stated aim is to set up an Islamic state in Nigeria, with their leader Abubakar Shekau saying: "We are fighting Christians."  Meanwhile the Nigerian government has been accused of lamentable failures in protecting Christians.

Christians were encouraged to pray that the places where young men are being radicalised will be exposed, and to pray for courage and boldness for the Nigerian government and the international community as they fight the 'virus' of extremism. During the event a member of the Nigerian High Commission was prayed for on stage by young Nigerians, and he in turn prayed for them.

People were also encouraged to pray for the persecutors themselves, being reminded of Saul in the New Testament; once a persecutor of Christians but later a godly leader persecuted for Christ.

Pastor Fred Williams of Love Jos attended the vigil along with other Christians from various parts of Nigeria affected by Boko Haram's violence. Pastor Fred said: "There is something stronger than terror, and that is love. Prayer without action is hypocrisy. We need to love back; defiance expressed creatively in practical terms."

Pastor Fred shared stories of Christians standing up and loving communities deeply impacted by the violence of Islamist extremism. They include a young Nigerian man who has set up Trinity Christian Academy in Taraba, providing boarding education for more than 250 children from over 25 villages, despite limited accommodation and water supplies.

"We cannot just pray but must also act," Pastor Fred said. "The Church must not draw back. We must take care of the children in Nigeria, making sure there are no foot soldiers for Boko Haram to take."

Another Christian standing up against terror is Esther Banga, founder of the Women Without Walls Initiative (WOWWI). WOWWI's vision is to develop a non-violent, creative and inclusive approach for conflict resolution and transformation in Nigeria, through women who are natural agents for social and national change. Esther has organised peaceful protests where more than 10,000 women have joined together to call for change and an end to the violence. As well as a pressure group, WOWWI also educates orphans and raises funds for the rehabilitation of displaced women and children.

Release International chief executive Paul Robinson shared at the vigil that persecuted Christians across the world are so encouraged to hear that people are praying for them as their brothers and sisters in the global body of Christ.

No More Sorrow, a campaign focusing on Nigeria, is being launched this month by Release International. Release is an organisation serving the persecuted church around the world, and during a period of prayer last year they felt God leading them to focus on Nigeria in 2014.

With Nigeria's general election coming up in 2015, the campaign is particularly calling on the Nigerian government to provide comprehensive and effective protection for vulnerable Christian ahead of and during the election period. The campaign includes a petition to the Nigerian High Commission in the UK to protect Christians from extremist violence.

A song has been written by UK worship leader Noel Robinson, and this No More Sorrow track (available on i-tunes at the end of May) features a range of worship leaders from the Nigerian diaspora in the UK.

Paul Robinson said: "Christians – men, women and children – have suffered shocking violence at the hands of extremists in Nigeria and it doesn't look like ending any time soon. With the elections around the corner the fear is that attacks against government institutions and Christians will increase as militants attempt to influence the outcome.

"Please join us in this vital campaign by not only signing our petition but also praying and telling others so that they can raise their voices too. Too many Christians have been murdered, injured, bereaved and traumatised. They need our help. Please join them in praying for an end to the suffering in Nigeria."

Find out more: Read more about Release's No More Sorrow campaign.

Watch: Show the one-minute No More Sorrow campaign video in your church.

Donate: Give to Nigerian families affected by terror (donations processed through Christian Concern).

Take action: Sign a petition to the Nigerian High Commission in the UK to protect Christians from extremist violence.