A Russian opposition lawmaker has said in a formal inquiry that Foreign Minister Sergei Lavrov needs to explain why 89 politicians from 17 European countries have been banned from entering Russia.
Lawmaker Dmitry Gudkov said on May 31 that Lavrov also needed to confirm the names of all 89 individuals included in the ban.
The blacklist comes amid tensions between Moscow and the West over Russia's seizure and annexation of Crimea in March 2014 and its support for pro-Russian separatists in eastern Ukraine.
The EU has imposed sanctions, including asset freezes and travel bans, on 151 Russians and pro-Russian Ukrainians.
A Russian Foreign Ministry official confirmed that lists of banned individuals had been sent to EU states.
The list includes past and serving European parliamentarians and ministers who have been outspoken critics of President Vladimir Putin and Russia's actions in Ukraine.
TASS quoted the unidentified official as saying the blacklist "was done in answer to the sanctions campaign that has been waged in relation to Russia by several states of the European Union headed by Germany."
A spokesperson for EU foreign-policy chief Federica Mogherini said on May 30 that the measures were "totally arbitrary and unjustified, especially in the absence of any further clarification and transparency."
Governments have suspected the existence of such a list for some time and a number of politicians and officials have been stopped from entering Russia in recent months.
EU Parliament President Martin Schulz said the blacklist "further diminishes mutual trust."
Berlin said it demanded clarification from Moscow, adding that people on the list had a right to know why they have been included so they can take appropriate legal action.
"At a time when we are trying to defuse a bitter and dangerous conflict in the heart of Europe, this does not help," German Foreign Minister Frank-Walter Steinmeier said during a visit to Ukraine.
A spokeswoman for the Foreign Office in London said, "If Russia's intention is to put pressure on the EU to ease sanctions, then this is not the way to do it."
According to Swedish Foreign Minister Margot Wallstroem, "It is very striking behavior, which unfortunately does not improve Russia's image, and we have asked for a clarification for this conduct."
Dutch Foreign Minister Bert Koenders summoned the Russian ambassador, calling for transparency and justification of the travel bans.
In a blog post, however, Finland's Foreign Minister Timo Soini said it was pointless to "overdramatize" the issue.
"This is an expected reaction to the [EU] travel ban against Russian citizens," he wrote. "It's not a big surprise."
Meanwhile, the European politicians who discovered they were on the blacklist said they were proud of being included.
Anna Maria Corazza Bildt, a member of the European Parliament (MEP) and wife of former Swedish Foreign Minister Carl Bildt, said, "Those who try to censor us and make us scared for standing up for values deserve even more criticism."
"When I saw the other names [on the list], I found out I was in a very decent club," former Czech Foreign Minister Karel Schwarzenberg said. "I consider this a reward."
German MEP Rebecca Harms, who has previously been turned away by Russia, said the list targets politicians who are campaigning for Ukraine and for human rights, democracy, and civil society in Russia.
"Clearly," Harms added, "Vladimir Putin sees honest criticism over his authoritarian approach as a threat to his power."