"Embassy employees have visited Russian national Burkov, extradited from Israel to the US, at a pre-trial detention centre in Alexandria, in the state of Virginia. We are in constant contact with Alexei, his relatives and lawyer," the embassy said in a Facebook press release on Wednesday.
The statement added that Burkov is being provided with all the necessary consular legal assistance.
"We will seek compliance with his legal rights and interests," the embassy stressed.
The US District Court for the Eastern District of Virginia extended the detention of Burkov last week, without specifying how long he would be kept in custody.
Burkov is charged with running two websites for hackers, including one that was selling stolen bank card numbers that were used in more than $20 million worth of fraudulent purchases.
The charges include wire fraud, computer intrusions, identity theft, and money laundering. If convicted, Burkov faces a maximum sentence of 80 years in prison. However, actual sentences for federal crimes are typically less than the maximum prescribed penalties, according to the US Justice Department.
Prior to his extradition to the United States, Burkov spent almost four years in Israeli custody fighting unsuccessfully to be sent home while local authorities enforced a ban on his case in the media.