The staggering levels of persecution against Christians around the world is documented in a new 'Hall of Shame' list released by watchdog International Christian Concern (ICC).

ICC on Wednesday said that North Korea, Iraq, Syria and Nigeria were the worst state persecutors of Christians, while Saudi Arabia, Pakistan, China, India and Egypt were "perennial abusers of religious freedom".

The persecution watchdog also listed a third category, 'New and Noteworthy', in which it placed countries where "events... indicate declining religious freedom and are cause for alarm".

Within this list was the US, Russia and Mexico.

In North Korea, former prisoners described horrific torture witnessed in the country's notorious labour camps. One told ICC that prisoners were forced to stone each other to death, while another reported seeing the execution of entire families in gas chambers.

CSW, a UK-based religious freedom charity, said in a report released last September that freedom of religion or belief "is largely non-existent" under dictator Kim Jong-Un's leadership.

"Religious beliefs are seen as a threat to the loyalty demanded by the Supreme Leader, so anyone holding these beliefs is severely persecuted," the report said. "Christians suffer significantly because of the anti-revolutionary and imperialist labels attached to them by the country's leadership."

Among the documented incidents against Christians are "being hung on a cross over a fire, crushed under a steamroller, herded off bridges and trampled underfoot".

Isaac Six, advocacy director at ICC, previously told Christian Today it was "nearly impossible to imagine the horrors that are a daily reality for so many of faith in North Korea".

In Nigeria, ICC said Christians face "brutal daily persecution for their faith from the Islamic extremist groups Boko Haram and the Fulani militias".

The government's attempt to eradicate Boko Haram - whose leader has vowed to eradicate Christianity in Nigeria - has been "a massive failure overall", ICC said, and "has only refocused them [Boko Haram] on attacking Christians".

Meanwhile in Iraq and Syria, "Christianity... is on the verge of extinction," the report warned, and many of the hundreds of thousands of Christians who have fled the region in recent years are unlikely to return.

ICC condemned the "escalation of attacks on Christians" in India, and tactics of "intimidation, arrests, destruction of church property, and church closures" used against Chinese Christians by the Communist government.

"The government is the primary persecutor of Christians in China as it seeks to consolidate power over the people," the report said.

Russian President Vladimir Putin in July 2016 signed into law the 'Yarovaya' package, under which house churches are illegal and religious activity or evangelism is prohibited anywhere outside a registered church or religious site, including private homes and online. Only named members of religious organisations are now allowed to share their faith, and even informal witnessing between individuals is forbidden. Critics have branded it a draconian attempt to stifle religious freedom under the guise of clamping down on terrorism.

ICC said the Yarovaya laws "are just the most recent crackdown in a trend of stifling religious expression" in Russia, and named Pastor Donald Ossewaarde as one of a number of Christian missionaries to have been fined under the new legislation.

The inclusion of America in the "New and Noteworthy" category was because "Christians and all religious people are being marginalised through the law," the report said.

There has been "a broad cultural shift towards secularism" and "Anti-Christian entities have been able to leverage the growing secularisation of society and culture to their advantage, utilising the courts as a preferred venue to gradually marginalise and silence Christians."

"While there is no comparison between the life of a Christian in the US with persecuted believers overseas, ICC sees these worrying trends as an alarming indication of a decline in religious liberty in the United States," the report concluded.