Reed, a 29-year-old student and former marine from Texas, allegedly attacked police after attending a party in Moscow.

He appeared wearing a facemask in a cage for defendants in a courtroom in the Russian capital as the judge read out the guilty verdict, saying the police officers had suffered "mental and physical harm".

Reed was handed nine years in a penal colony, according to an AFP reporter in the courtroom.

"This is completely a political case," Reed told journalists after the verdict.

"I will be asking my government for political support".

The case has caught the attention of US diplomats in Russia and US Ambassador John Sullivan said he was following proceedings along with the trials of other Americans detained in Russia.

Reed has been held in a Moscow prison in pre-trial detention since August 2019. He pleaded not guilty to the charge, saying he remembers nothing of the incident.

His family has raised the alarm over what they say are irregularities in the proceedings and said the prosecution's request for a nearly 10-year sentence was unfair.

Reed's father Joey told reporters after the verdict was read out that he was planning to appeal directly to Russian President Vladimir Putin over the trial which he said was "completely corrupt".

"We are not arguing about Russian law, we are arguing about how Russian law is applied," he told reporters.

Reed's case has attracted attention owing to the lengthy sentence faced by a US citizen and speculation in Russian and US media that Reed could become part of a prisoner swap.

In June, Russia convicted US citizen Paul Whelan, also an ex-marine, to 16 years in a penal colony for espionage, prompting speculation he could participate in a prisoner swap.

Whelan's brother David said in a statement on Wednesday that "our family is not privy to government discussions, if there are any, about Paul's case".

Sullivan has also raised concerns over the case against Michael Calvey, a high-profile American investor who was arrested last year for allegedly defrauding a Russian bank.