MOSCOW — A Russian court convicted a journalist for Ukraine's state news agency Monday of spying and sentenced him to 12 years in prison.

Ukrinform correspondent Roman Sushchenko has been in custody since his 2016 arrest by Russia's top domestic security agency, the FSB. The FSB alleged he was a Ukrainian military intelligence officer collecting sensitive information about the Russian armed forces. Sushchenko denied the accusation.

Ukrainian President Petro Poroshenko denounced Monday's verdict by the Moscow City Court as a show of "unprecedented cynicism." The Ukrainian Foreign Ministry demanded the journalist's immediate release.

Harlem Desir, a media freedom representative at the Organization for Security and Cooperation in Europe, a top security and rights group, deplored the sentence and reiterated his call for Sushchenko to be let go.

The New York-based Committee to Protect Journalists also urged Russia to immediately set Sushchenko free.

Sushchenko's sentencing comes amid a bitter tug-of-war between Ukraine and Russia, triggered by Russia's annexation of Crimea in 2014 and its support for separatist rebels in eastern Ukraine.

Last month, Ukraine's state security agency raided offices of state-owned Russian media outlets and arrested the head of Ukraine's office of the Russian state RIA-Novosti news agency, Kirill Vyshinskiy.

Vyshinskiy was detained on treason charges pending an investigation. Moscow has angrily assailed his jailing as an attack on freedom of speech.