Diplomatic relations between America and Russia have deteriorated to such an extent that contacts between the two countries have become extremely paranoid of one another, the chief executive of Russia’s largest bank has told CNBC.

“From what we see here in Russia and from the programs we see from the U.S., the unfolding situation is fairly complex. And there are certain signs of a certain … paranoid attitude to Russia and to every single contact with Russia real or imagined,” Herman Gref, Sberbank CEO, said via a translator.

The White House has been enveloped in political turmoil since last week, after President Donald Trump fired James Comey, then director of the FBI, as it investigated possible ties between the Trump campaign team and the Kremlin.

U.S. intelligence agencies believe Moscow tried to advance the likelihood of a Trump victory in November’s presidential election. At a news conference on Thursday, Trump again denied any collusion with Russian contacts during his election campaign.

When asked whether Gref harbored any concerns about the consequences of having met with Trump in the past, he replied, “I think the situation has become extremely paranoid for one to suspect that these sort of contacts could lead to political consequences.”