There has been a steep increase in persecution across the "10/40 window" in the last decade, says Gospel for Asia.

It warned that in India alone there had been a "400 per cent" increase in persecution.

The 10/40 window encompasses the countries that have been least reached with the Gospel.

Gospel for Asia president K P Yohannan said that people who had not experienced persecution "do not fully understand what it means to have their lives threatened, homes destroyed, rights violated and loved ones imprisoned, all because of embracing faith in Jesus Christ".

"In the 14 countries we serve, persecution of this sort has become a normal way of life, especially for those directly involved in mission work," he said.

Christians in the 10/40 region have had their homes destroyed or been imprisoned because of accusations against them, including accusations of forced conversions. Many have been killed because of their belief in Christ and others have been forced to go underground.

"The increase of this kind of persecution should not be surprising where the gospel is going forth in unfriendly world areas," said Yohannan. "Jesus sent His disciples out as sheep among wolves (Matthew 10). Historically and biblically, persecution is an anticipated part of serving God."

Christians around the world spent Thursday praying for believers who are suffering for their faith as part of the annual International Day of Prayer for the Persecuted Church.

Yohannan said the prayers of others were a strength and encouragement to those experiencing persecution, especially those who are in remote areas and feel alone in their struggle.

He said: "Suffering is forced upon our brothers and sisters.

"To those of us not experiencing the normality of persecution, Jesus is asking that we participate willingly in their suffering and chains.

"Through our prayers, we can be agents of God's divine healing, hope and help."