What is the name of this character from The Blacklist?

I was watching Season 7 of The Blacklist on Netflix and then I found a character who speaks to Mr Reddingston but I have no idea who that character is or what his name is.

He appears around minute 3 of the 5 episode of season 7, here is a picture of him:

Does anyone happen to know who that is?

My research led me to conclude that this should be an old friend of Reddington's. His name is Ilya Koslov and was a KGB agent.

The actor's name is Brett Cullen.

Thank you!