President of Ukraine Petro Poroshenko wrote on Facebook, Censor.NET reports.
"'Bykivnia graves memorial is perhaps the largest mass grave in Ukraine, where dozens and tens of thousands of innocently murdered people are buried. I ask you to honor memory of everyone who lies in mass graves across the former empire," Poroshenko wrote.
The Bykivnia graves is a National Historic Memorial on the site of the former village of Bykivnia on the outskirts of Kyiv. During the Stalinist period in the Soviet Union, it was one of the unmarked mass grave sites where the NKVD, the Soviet secret police, disposed of thousands of executed "enemies of the Soviet state".
The number of dead bodies buried there is estimated between "dozens of thousand," to 30,000, and up to 120,000.