As Boko Haram expands its attacks across neighbouring Cameroon, a Nigerian Archbishop has urged Christians to "storm the heavens" in prayer.

"We thank God for his mercy and faithfulness. We may not have received everything we prayed for, but by his grace most of us are still alive and we have remained one people and one nation," Archbishop of Jos, Ignatius A Kaigama of Jos, Nigeria, told those gathered at an overnight National Prayer Pilgrimage last week.

"Today, gauging the general despair and disillusionment in the land, we converge here again to cry on to the Lord for enduring peace and for God to stir strongly in the hearts of Nigerians the spirit to transcend narrow ethnic, religious, and political boundaries so as to always pursue the common good."

The Archbishop, who is also the president of the Nigerian episcopal conference, said that "fervent prayer" is necessary to bring together a nation fractured by militant attacks. "As Catholics, we believe that prayer, made with deep faith, can move mountains and calm storms and that prayer is our most powerful weapon as we face the multidimensional challenges in contemporary Nigeria," he added.

However, he also insisted that "prayer alone without good works is inadequate," and called on all Nigerians to work together for common good.

"Not to do our work well, to wish your neighbour harm or to engage in bitter, hostile, antagonistic political, religious or ethnic struggles that lead to loss of lives and the destruction of property and still claim to be people of faith is mere religious externalism devoid of godliness," he said.

"Our invitation to prayer is not meant to be a substitute for individual responsibility where we each play our parts to contribute to the welfare of all of us and our nation. With good behaviour, good works and fervent prayers, we can overcome all obstacles and rise to the highest heights."

Branding increasing attacks from militant group Boko Haram "cruel acts", the Archbishop also paid tribute to the girls abducted from their school in northern Nigeria in April, over 200 of whom remain missing.

"Our darling innocent school girls from Chibok are still being held over six months since their abduction. Only God knows the psychological and physical trauma they are going through," he said.

Suggesting that the 2015 elections could lead to an "explosive" political situation in Nigeria, the Archbishop implored: "Brothers and sisters, there is no better time to storm the heavens with prayers and petitions than now."

"Even though this is a Catholic Christian event, we call on all people of faith to join us in prayer, praying according to their religious tradition," he continued.

"Instead of using religion to cause strife, division and violence, we should unite and cry on to God. 2 Chronicles 7:14 reminds us of God's consoling words: "if my people who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then I will hear from heaven and I will forgive their sin and will heal their land.'"

A Nigerian commander told AFP news agency this week that Boko Haram, which means 'Western education is sacrilege', is attempting to create a Muslim caliphate across both Cameroon and Nigeria.

"Until now, the military presence has endured major skirmishes. But if Boko Haram decided to launch a major offensive, they could break through Cameroon's lines without too much difficulty," the agency was told by an anonymous security source.

A religious freedom report from Aid to the Church in Need has rated the state of persecution or discriminating facing faith groups in Nigeria as 'High', with the situation having "significantly deteriorated" in recent months.

"Many of our people are forced out of their ancestral homes," said Father Gideon Obasogie, a spokesman for the Diocese if Maiduguri. "Right now, thousands are living in caves on the mountains."