Islamic State militants recently executed 160 children and women for a variety of alleged offences including refusal to fast during Ramadan and sorcery, the UK-based organisation Syrian Observatory for Human Rights revealed.

The latest killings brought the number of ISIS victims in the Middle East to over 3,000 since the jihadists declared a state or caliphate of their own in June last year, the Syrian Observatory said.

"Many of the charges against those executed are recorded as blasphemy and spying, but others include sorcery, sodomy, practising as a Shia Muslim," the human rights group said.

The children and women met unholy deaths in the hands of ISIS as they were accused of practising "magic" and for refusing to fast, Fox News reported.

This week, two children were crucified in the Mayadin, Deir Ezzor province in eastern Syria after ISIS leaders accused them of "improper fasting" during the Islamic month of Ramadan, which runs from June 17 to July 17.

The bodies of the children, whose ages were left out, were put on public display on crossbars, each with a sign stating their offence.

The jihadist group has been trying to justify its inhumane executions by its twisted and medieval interpretation of the Koran as it claims that its followers are the true practitioners of Islam, according to experts.

"Underlying all these executions is the apocalypse ideology of the final battle between the believers and the unbelievers," said Jasmine Opperman, the director of Southern Africa Operations at the Terrorism, Research & Analysis Consortium.

"ISIS is using executions to show its followers—and would-be followers—that the group is the only true representative of believers, not only in word, but action, which is why executions are featured so prominently."

Other children, said the Syrian Observatory, died fighting for their lives.

"The violent Islamist group appears to demonstrate a particular interest in children, releasing videos of children fighting in cages and undertaking military training," the human rights group said.

The report also detailed moves undertaken by the group to entice children to join, which include setting up offices called "cubs of the caliphate" that recruit children to fight for ISIS.

Children from different backgrounds, including Kurdish, Yazidi, Christian and even Muslim, have been victims of ISIS, the United Nations Committee on the Rights of the Child said in a report submitted in February. They have been tortured, crucified, buried alive, used as suicide bombers and sold as sex slaves. Even those mentally-challenged have not been spared from the ISIS' terror campaign.

"ISIS is hoping to spur current supporters around the world who are dormant—of which there are millions—into joining their caliphate by advertising acts like these," said Ryan Mauro, a national security analyst for the non-profit group Clarion Project.

"They know that they can greatly increase their numbers by appealing to current radicals rather than the broader masses," he said.

Women have not been shown mercy by the ISIS either, with ISIS beheading two married couples in public this week for "sorcery."

"The Islamic State group executed two women by beheading them in Deir Ezzor province, and this is the first time the Observatory has documented women being killed by the group in this manner," said Rami Abdel Rahman, of the Syrian Observatory for Human Rights.

"The practising of anything that is not approved by the Islamic State under their very strict interpretation of Islam is 'haram' or forbidden," said Veryan Khan, editorial director for the Florida-based Terrorism, Research & Analysis Consortium.

"If the Islamic State thinks that sorcery is real, then black magic would be a threat to them and seen as a danger."