Maria Zakharova, spokeswoman for the Russian Ministry of Foreign Affairs, said officials in the United States sent back visa documents, saying the deadline for submitting documents was too early.

The Kremlin negatively accepted the refusal and promised to give a tough answer. US ambassador John Hanteman was summoned to the Moscow Foreign Ministry, but the deputy, Huntsman, went instead.

A little later, Zakharova said that Sergey Lavrov would clarify the necessary information on the problem with the US Secretary of State.