Following the US withdrawal and the Taliban's return to power, Afghanistan has been chosen as the worst country for Christian persecution by a religious freedom advocacy group.

International Christian Concern (ICC) said the US's chaotic withdrawal from Afghanistan "put a death sentence on Christians".

Under the Taliban, beatings, kidnappings, torture and murder of Christians and other minorities have "increased dramatically".

"Within the Taliban's hardline fundamentalist version of Islam, Afghan Christians—many of whom are former Muslims—are branded as apostates deserving of death," ICC said.

"By the end of 2021, the Taliban employed harsh tactics to expose the country's Christians and implement their Islamic justice. This brought persecution in Afghanistan to its highest levels since the Taliban's first government in 1996."

The award for the worst persecuting entity was given to Fulani militants, a radicalised faction of the wider Fulani people group - the largest nomadic ethnic group in Nigeria. 

ICC said they were responsible for killing tens of thousands of Christians since 2000 and that is suspected they are being "aided by stakeholders within the Nigerian government". 

"Nigeria is arguably one of the most dangerous places on the planet for Christians because of the abundance of violent extremists, including groups of Fulani militants," it said.

"This faction of a broader nomadic group, through its exposure to Islamic fundamentalist ideologies, has terrorized Nigeria's Christian communities.

"Radicalized and armed Islamist Fulani militias have killed tens of thousands of Christians and left countless homeless in a 20-year genocide.

"The Nigerian government claims to be countering this extremism but is mostly lip service as the conflict grows out of control. Many point to government inaction as one of the reasons for increasing Fulani militant violence against Nigeria's Christian population in the Middle Belt.

The individual award went to Ayatollah Ali Khamenei, the Grand Ayatollah and Supreme Leader of Iran, because he "allows the torture and execution of many Iranian Christians".

"Those found attempting to share their faith or worship in a house church are often arrested and sent to the notorious Evin Prison, known for its brutality and torture of prisoners," ICC said.

"The Grand Ayatollah at the helm of Iran directs persecution by controlling every aspect of Iranian life and dealing grave consequences to those who do not conform to his strict conservative ideologies."

Jeff King, president of ICC, said, "Across the globe, Christians are beaten, imprisoned, tortured, and murdered simply because of what they believe in. I've been doing this for 20 years and it's not getting better but getting worse.

"Religious freedom is often a very complicated subject. This annual report is a primer for our allies to understand it and see it."