CIA Agent arrested in Russia

A CIA agent is arrested in Moscow and charged with spying. The agent is fluent in Russian and has had years of specialised training on how to blend in with the Russian people. he's the perfect sleeper agent.
Down in the darkest dungeons beneath Kremlin the Russian Secret Service (FSS) begin their interrogation.
"We know you are American, spy Pig. Admit it!"
"How can you say that? I speak Russian like a Muscovite, I am Russian."
"You are lying, Spy Pig. We know you are a Yankee dog. Admit it"
The Agent pulls a copy of Pushkin from his jacket pocket and begins to read aloud. Within minutes the guards are weeping with joy at how beautifully the poetry is read.
"You see, only a Russian can read Pushkin like this", said the agent.
"You lie, Spy Pig, I know you are an American, confess".
The agent calls one the of the guards to play Kalinka on his balalaika. The agent leaps on to the table a dances a Russian folk dance whilst singing. The guards clap and cheer having seldom seen such a perfect performance.
"You see no one can sing the most loved song in Russia like this if you are not a Russian."
"You lie Yankee snail pig. I know you are an American".
The agent calls of 6 bottles of Siberian vodka and over the next hour drinks them all finally smashing his glass on the table.
"No one drinks vodka like a Russian and I am a Russian"
Impressed the FSS agent claps his hands slowly.
"You are good Yankee Pig poo, very good, but I know you are not Russian and now you die".
The CIA agent slumps in his seat knowing he is defeated.
"Tell me one thing, how did you know? I am highly trained can speak, read Pushkin, sing and dance and drink like a Russian. My cover was perfect. How did you know I am an American?"

"It was easy Yankee man, we have no Blacks in Russia"