Russia has banned 89 EU citizens from entering the country, including British MI5 and MI6 chiefs.
The disclosure comes after a number of EU politicians had tried to travel to Russia in recent months only to be told at the border that they could not enter because they were on the list.
An EU spokesman said the list had now been handed over after repeated requests for details from the EU and the member states concerned.
"The list with 89 names has now been shared by the Russian authorities. We don't have any other information on legal basis, criteria and process of this decision", the spokesman said.
"We consider this measure as totally arbitrary and unjustified, especially in the absence of any further clarification and transparency. We are keeping in close contact with the member states involved."
MI5 Director General Andrew Parker and the former MI6 chief Sir John Sawers are among the other British names on what appears to be a leaked version of the list circulating online.
Among the names on the list is the former British deputy prime minister Nick Clegg as well as other former members of the British government.
The British Foreign Office said the existence of the list would make no difference to EU sanctions imposed in response to Russia's support for separatist rebels fighting government forces in eastern Ukraine.
Other names include the former Belgian prime minister Guy Verhofstadt and French philosopher Bernard-Henri Levy.
A Polish politician and MEP released the leaked list.
Full list of 89 persons from EU blacklisted / banned by Russia http://t.co/CaNYCUC2PL— Jacek Saryusz-Wolski (@JSaryuszWolski) May 30, 2015