A spokesperson for UN Secretary-General Antonio Guterres said on Wednesday that the power and authority to launch international follow-up criminal investigations on Saudi journalist Jamal Khashoggi's death lie with UN member states.

Stephane Dujarric, the spokesperson, told the press that the UN chief does not have the power or the authority to launch criminal investigations without a mandate from a competent intergovernmental body.

Earlier in the day, a United Nations special rapporteur said in a report that the Saudi journalist was the victim of a premeditated extrajudicial execution, for which the State of Saudi Arabia is responsible.

The special rapporteur determined that there was credible evidence, warranting further investigation of high-level Saudi officials' liability, including that of the Crown Prince, and suggested the UN secretary-general to establish an international follow-up criminal investigation.

"If a full and effective criminal investigation is not conducted by Member States, the only way to effectively pursue an investigation, requiring the cooperation of relevant Member States, would be through a resolution of the Security Council, under the appropriate Charter provisions," said Dujarric.

"It's not for the Secretary-General to agree or not agree with what the Special Rapporteur reports," said the spokesperson.

"What is clear for the Secretary-General, as he's been saying from the beginning, is that there needs to be a full and transparent investigation," he added.

Khashoggi was murdered inside the Saudi consulate in Turkey's Istanbul in October 2018.