The United Nations has formally denounced the murders of Moisés Sánchez Cerezo, a Mexican journalist recently found killed weeks after his disappearance, and Kenji Goto, a Japanese freelancer assassinated by Islamist extremists in Syria.

“His [Sánchez Cerezo's] killing is an unacceptable attack on journalism, a profession that embodies the right of freedom of expression, which is indispensable to democracy," Irina Bokova, Director-General of the U.N. Educational, Scientific and Cultural Organization, said in a statement as reported by the U.N. News Centre.

Bokova called “on the Mexican authorities to shed light on this crime and bring its perpetrators to justice.”

The decapitated body of Sánchez Cerezo was discovered on Jan. 24, three weeks after he was abducted from his home by armed men. In his role as the owner and editor of weekly magazine La Unión, Mr. Sánchez Cerezo often denounced problems of insecurity in the Mexican city of Medellin de Bravo, which is located in the state of Veracruz.

Sánchez Cerezo's death took place at a time of deteriorating security across the whole of Mexico; numerous Mexican journalists and activists have in the last few years lost their lives. A report released in March 2014 by UNESCO states that, worldwide, more than 430 journalists were killed between 2007 and 2012.

Meanwhile, in a separate statement Bokova  condemned the murder of Japanese freelance journalist Goto at the hands of the Islamic State of Iraq and the Levant. Goto was a seasoned war journalist who had worked in the past in Afghanistan and Syria. On Jan. 31, ISIL released a video of his beheading.

"His cold-blooded murder was a vile act that I condemn in the strongest possible terms," Bokova said.

Bokova went on to “urge the authorities to do everything within their power to bring the perpetrators of this crime to justice."