World governments must "stop turning a blind eye" to the "slaughter" of Christians, Release International said.
The religious freedom charity is calling on the UK government to lead the way by taking "a decisive stand" against "rapidly rising" Christian persecution around the world.
The call comes a day before the UK government hosts a ministerial on religious freedom bringing together over 500 government and faith representatives from around the world.
The ministerial is being held three years after the government-commissioned Truro report called for bold action to address widespread Christian persecution.
Speaking ahead of the two-day gathering, Release International CEO Paul Robinson said: "How many more Christians have to die for their faith before governments around the world take decisive action?
"The Truro Review has recognised that 80 percent of the violence against faith groups worldwide is directed against Christians. The scale is horrific, and the problem is getting worse by the day."
He urged the government to implement the recommendations of the Truro report "in full" and make it "a clear priority".
The Prime Minister's Special Envoy for Freedom of Religion or Belief (FoRB), Fiona Bruce, added, "Some 360 million Christians around the world suffer persecution for their faith. Somewhere in the world every two hours a Christian is killed for their faith."
Release International will be hosting a seminar at the Christians in Parliament Prayer Breakfast on day one of the ministerial.
The seminar will examine the growing violence in Nigeria and the Sahel region of Africa.
The keynote address will be given by a Release International partner from Burkina Faso who is not being named for security reasons.
"Many people try to say that these are simply tribal wars. But what we see is the radicalisation of Muslims," she said.
"The jihadists are trying to make an Islamic State of Greater Sahara. It is obvious that this is a religious conflict.
"Christians are killed on the spot. If you're kidnapped and you're a believer, there is no possibility you will survive."
The seminar will also hear about the situation in Nigeria from the Anglican Archbishop of Jos, Benjamin Kwashi.
In a video message, he says, "Since 2001, not less than 20,000 Christians have been killed in Plateau State alone. And the world is silent.
"Boko Haram has joined forces with ISWAP (Islamic State West Africa Province) and they have one goal – to Islamise Nigeria. Their first target is the Church."
The Evangelical Alliance has said that the ministerial must lead to a long-term strategy by the UK Foreign, Commonwealth and Development Office to advance FoRB.
Danny Webster, director of advocacy at the Evangelical Alliance, said: "At the summit this week, words must be matched with action.
"Protecting and promoting human rights should be a cornerstone of our government's foreign policy, trade deals and overseas development spending.
"Religious freedom is foundational to free societies and should be at the centre of government action across the globe."