A member of Russia's parliament has formally requested that foreign minister Sergey Lavrov confirm and explain the list of 89 European politicians who have been banned entry to Russia.
Russia has shared the list with European Union officials, but has refused to release it.
A leaked list published by the Finnish public broadcasting company Yle includes politicians from 17 EU countries, but no explanation for the bans.
The EU has criticised the Russian move as "totally arbitrary and unjustified, especially in the absence of any further clarification".
Dmitry Gudkov, the sole member of Russia's parliament who opposes the Kremlin, asked Lavrov today to confirm the names and to state why they were included.
The EU has imposed sanctions and some travel bans on Russia for its actions in Ukraine.