UK churches are being asked to pray for Eritrea where a history of persecution against Christians is threatening to spill over into neighbouring Ethiopia.
Release International says priests are being targeted and killed by Eritrean forces who have joined fighting in Tigray, northern Ethiopia.
Orthodox Church sources say at least 78 priests were killed by Eritrean forces during a massacre of hundreds of civilians in the sacred city of Askum in November last year.
Helen Berhane, a former prisoner of faith in Eritrea and now a religious freedom advocate, has warned that the terror spree continues.
"Eritrean troops are killing a lot of priests and raping their wives," she told Release International.
"Some of the priests stand holding their crosses, so they cut their hands. And when the soldiers ask the priests to remove their hats, when they say no, they shoot them.
"Hundreds of priests are dying in this conflict at the hands of Eritrean soldiers."
Release International is asking people to pray for Eritrea on the International Day of Prayer for the Persecuted Church (IDOP) on Sunday and has created free resources to be used in churches.
Eritrea has a decades-long record of persecuting Christians after closing most churches in 2002. The following years have seen Christians arrested, detained - sometimes indefinitely, and tortured.
Berhane, who was once locked up in a shipping container that was freezing at night and baking hot during the day, is asking Christians to fast and pray for believers in Eritrea.
"I fast, not to change the situation, but to discipline myself and to understand. I ask God, 'What's going on? What is happening?'" she said.
"Always I pray and sing and read my Bible. I find encouraging words in the Bible. We are in hard times, so we need to fast and pray."
Some Eritrean Christians fled over the border to Ethiopia where they found safety in refugee camps, but the conflict in Tigray has put them at risk once again.
"Please pray for protection for these Christians, and pray for grace that they can receive with joy the suffering they are facing, because they're doing it for the sake of Christ," said Dr Berhane Asmelash, a human rights campaigner and Release partner.
Release CEO Paul Robinson is also asking Christians in the UK to remember their persecuted brothers and sisters in Eritrea.
"We need to stand with them, help bear their burdens, and join them in prayer for a new day of freedom for their country," he said.
Despite fierce persecution, Dr Asmelash says Christianity has continued to grow in the country.
"Christians have been the most persecuted group of people in Eritrea. It is because they won't stop gathering and won't stop worshipping. It is beyond the government's control," he said.
Dr Asmelash believes there are at least 180 Christians behind bars in Eritrea. Some were released in the last year, possibly in an effort to contain Covid in the country's overcrowded prisons, but over the summer dozens were re-arrested, dashing hopes of a change of heart within the government.
"We don't see any change in the government's policy," said Dr Asmelash.
"The government is not gaining anything by arresting these Christians. There are many talented people inside prison, who could contribute a great deal to their country.
"So, my message to the government of Eritrea is release them. Their families, their children, their wives and their husbands need them."
Release International, Christian Solidarity Worldwide, the Evangelical Alliance and Open Doors are hosting a special live online event for IDOP at 7.30pm on Sunday 7 November. To register for the event, click here.