The head of UNESCO on Saturday "firmly condemned" the killing of Saudi journalist Jamal Khashoggi.
Khashoggi, a Saudi journalist and columnist for The Washington Post, had gone missing since entering the Saudi Consulate in Istanbul on Oct. 2.
After days of denying to know his whereabouts, Saudi Arabia on Saturday claimed Khashoggi died during a fight inside the consulate.
"I firmly condemn the assassination of Jamal Khashoggi," UNESCO Director-General Audrey Azoulay said in a statement.
"The killing of Jamal Khashoggi reminds us of the need to fight for press freedom, which is essential to democracy. Accountability for these crimes is non-negotiable," Azoulay said.
"I urge the relevant authorities to conduct a thorough investigation into this crime and bring its perpetrators to justice," she added.
The statement also recalled the International Day to End Impunity for Crimes Against Journalists which UNESCO will mark on Nov. 2.
On the day of Khashoggi’s disappearance, 15 other Saudis, including several officials, arrived in Istanbul on two planes and visited the consulate while he was still inside, according to Turkish police sources.
All of the identified individuals have since left Turkey.
A joint Turkish-Saudi team completed an investigation into the case on Thursday after searching the residence of the consul general as well as the Saudi Consulate in Istanbul.