"This crime is, yet again, a tragic reminder of the increasing dangers journalists face every day in Syria," Xinhua quoted the security council members as saying in a statement to the press in which they expressed deep sympathy and condolences to Sotloff's family.
"It also once again demonstrates the brutality of ISIL, which is responsible for thousands of abuses against the Syrian and Iraqi people," the Council members said, underlining the need to bring perpetrators of the reprehensible act of terrorism to justice.
The militant group Tuesday released a video online that appears to show the beheading of US journalist Sotloff.
The 15-nation body stressed again that ISIL (Islamic State of Iraq and the Levant) must be defeated and that the "intolerance, violence and hatred" it espouses must be stamped out.
"The members of the Council further emphasised that such continued acts of barbarism perpetrated by ISIL do not intimidate them but rather stiffen their resolve that there has to be a common effort amongst governments and institutions, including those in the region most affected, to counter ISIL, Al-Nusra Front and all other individuals, groups, undertakings, and entities associated with Al Qaeda," the statement said.
The most powerful body of the UN demanded the "immediate, safe and unconditional" release of all those who are kept hostage by those militant groups.
ISIL, also known as the Islamic State of Iraq and Syria (ISIS) or the Islamic State (IS), has recently claimed to have established an "Islamic Caliphate" in parts of Syria and Iraq, threatening the stability of the region.