WARSAW, Poland (AP) — A Ukrainian journalist convicted in Russia of spying and jailed for three years has described how he created paintings of cathedrals, lighthouses and soothing landscapes as a form of psychological therapy during his imprisonment.

Roman Sushchenko, who denies spying, says he would use unconventional materials, including ketchup and onions, for paints.

He says his artwork “helped keep me alive.” Sushchenko sent his works to his family by mail — with only one failing to arrive.

A reporter for Ukrinform, Ukraine’s state news agency, Sushchenko was imprisoned from 2016 until his release in September under a Russian-Ukrainian prisoner exchange.

He spoke at a news conference Tuesday organized by the Polish Journalists Association — which is exhibiting reproductions of his works — and the Ukrainian Embassy in Warsaw.