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..."