In countries such as Iran, North Korea and Syria, believers are regularly targeted and often killed for their faith.
Earlier this month in Pakistan a Christian couple were burned alive by a mob of Muslims.
Top 5 countries with religious oppression
- Iraq
- Libya
- Nigeria
- Pakistan
- Sudan
Two hundred million Christians around the world suffer because of their faith whilst 75% of the world's population lives in countries with high or very high restrictions on religion.
Mervyn Thomas from Christian Solidarity Worldwide told Premier prayer can make a huge difference.
"It is so often the key to unlocking doors, unlocking prison cells and unlocking difficult situations," he said.
He added: "One of the things we should thank God for is the fact that we're free in this country.
"We're free to pray, we're free to protest and we're free to do all of the things which millions and millions of our family around the world are not able to do."
The International Day of Prayer was formed by a coalition of Christian charities including Release international, the Evangelical Alliance and Open Doors.