A spokesperson for the UN Office of the High Commissioner for Human Rights (OHCHR) said Friday that the body was “deeply concerned” by Vietnam’s use of ill-defined laws to suppress media freedom.

The criticism comes after three journalists were found guilty of “making, storing, spreading information, materials, items for the purpose of opposing the State” under Article 117 of the Vietnamese Criminal Code and sentenced to between 11 and 15 years in prison on Tuesday. OHCHR spokesperson Ravina Shamdasani said that this was “a disturbing development that appears to be part of an increasing clampdown on the freedom of expression in the country.”

Freedom of expression is protected under Article 19 of the International Covenant on Civil and Political Rights (ICCPR), to which Vietnam is a party. Shamdasani warned that Vietnam’s detention of an increasing number of independent journalists, bloggers, online commentators and human rights defenders is a violation of the country’s obligations, apparently echoing the unheeded calls of a number of UN human rights mechanisms, including the UN Human Rights Committee.

Shamdasani urged Vietnam to cease its use of serious criminal charges to suppress free expression, to unconditionally release all those who have been detained to that end, and to revise its criminal code in line with Article 19 of the ICCPR.