MOSCOW, May 8 -- Russia on Thursday vowed to retaliate upon new sanctions from the United States and Canada, but stressed it would not publicize those who were placed on the Russian blacklist.

"Of course, we will not leave such unfriendly actions unanswered," Russian Foreign Ministry spokesman Alexander Lukashevich told reporters. "Sanctions are not our method, but unfriendly actions force us to give a rebuff."

The names of new persons on the Russian "stop-list" would not be made public, but those people will learn about that when they apply for a visa, he said.

"We did not run after quantity and did not make a show, unlike the Americans and Canadians," Lukashevich was quoted by the Interfax news agency as saying.

The United States banned a bunch of Russian politicians and business leaders from entry in mid-March in the first wave of sanctions against Moscow's accession of Crimea, followed by the European Union and Japan.

On April 28, Washington slapped fresh sanctions against seven Russian officials and 17 companies amid rising tension in Ukraine.

Russian Deputy Foreign Minister Sergei Ryabkov has said the latest package of U.S. sanctions would negatively affect Russia's high-tech industry.

The Standard & Poor's rating agency has downgraded Russia's long-term rating as well as ratings of a number of Russian companies amid the wave of sanctions imposed by the West against Moscow.