The Islamic State jihadist organisation is sending teams of trained assassins into refugee camps disguised as refugees to either kidnap or kill Christians, aid workers at a UN-run camp in Jordan revealed, according to the Sunday Express.

Following this disclosure, concerns were raised that the ISIS assassins hiding among the refugees could eventually find their way to Britain since the UK government has already promised to take 20,000 people from these refugee camps in the Middle East, the British paper reported on Sunday, warning that once the jihadis disguised as refugees land in UK, they could begin unleashing terror on the streets of Britain.

The ISIS ploy was discovered after one of the assassins sent to a refugee camp in Jordan suddenly had a change of heart after seeing how Christian workers were helping the refugees inside the camp, the Express said.

The UN aid worker who made the revelation—who declined to be identified for security reasons—said the would-be ISIS assassin even renounced jihad after seeing how his fellow Syrians were being treated kindly by the Christian workers. The ISIS agent then revealed to authorities in the camp that the jihadist group had sent other trained killers to various refugee camps in Jordan and elsewhere as part of the ISIS plot to either kill or subjugate Christians and wipe Christianity off the map, the Express said.

The unnamed ISIS agent also reportedly revealed that his group has sent gangsters to the refugee camps to kidnap young refugee girls and sell them as sex slaves.

The UN aid worker who made the disclosure said the ISIS agent's revelations only served to confirm what the aid workers are already seeing in the refugee camp.

"The Muslim gangs come as refugees, but they have their agendas. They're like a mafia. People are even killed inside the camps, and the refugees are afraid to say if they saw somebody get killed. If you ask them, they'll say, 'I don't know, I was asleep,'" the aid worker said, adding that the refugees are forced to keep quiet for fear of their own lives.

Cameron urged to recognise that Mideast Christians face genocide

Meanwhile British Prime Minister David Cameron has received a letter, written by Lord Alton of Liverpool and Baroness Cox, asking him to "urgently consider" the plight of Christian refugees in Syria, the Sunday Express reported.

The letter noted that "many Christian refugees, having been terrorised by IS in Syria and Iraq, have had to leave the refugee camps because of cruelties inflicted upon them inside the camps."

Late last week, about 70,000 Christians reportedly fled Syria's largest city, Aleppo, amid intensifying ISIS attacks.

In his letter, Lord Alton told Cameron that Britain should prioritise Christians in extending shelter and other assistance to the refugees since there are many Islamic countries in the region that can offer safe haven to Muslims.

"The government must realise that what Christians in the Middle East are experiencing is genocide, and nothing less," Lord Alton told the British prime minister.