The lawyer for adult film star Stormy Daniels says US President Donald Trump’s longtime lawyer Michael Cohen received $US500,000 ($665,000) from a Russian billionaire in the months after the 2016 US election.

In a tweet and report released on Tuesday, Ms Daniels’ lawyer Michael Avenatti said a company controlled by Viktor Vekselberg, a businessman with ties to Russian President Vladimir Putin, sent the payment to Mr Cohen.

It comes after Mr Avenatti claimed Mr Cohen paid Ms Daniels $US130,000 to stay quiet about a sexual encounter with Mr Trump.

It is not clear how Mr Avenatti would have knowledge of any payment from Mr Vekselberg to Mr Cohen. Mr Cohen and Mr Avenatti did not immediately respond to requests for comment.

Mr Avenatti said Mr Vekselberg and his cousin, Andrew Intrater, made eight transfers to Mr Cohen between January and August 2017 through a company called Columbus Nova LLC for a total of $US500,000.

Columbus Nova is a US investment arm of Renova Group, a conglomerate controlled by Mr Vekselberg. Both Mr Vekselberg and Renova were hit last month by US sanctions for suspected meddling in the 2016 US election and other alleged “malign activity”.

Mr Vekselberg and Mr Intrater could not be immediately reached for comment. An executive at Columbus Nova did not immediately respond to a request for comment.

The New York Times reported last week that Mr Vekselberg was questioned by agents working for Special Counsel Robert Mueller earlier this year, as part of their investigation into Russian interference in the 2016 US elections.

Mr Avenatti also said he discovered four payments of just under $US100,000 each by drugmaker Novartis to Essential Consultants, the same company used by Mr Cohen to make payments to Ms Daniels.

Novartis did not immediately respond to a request for comment.