Russia is "ready" to discuss a prisoner swap with Washington at the presidential level, its foreign minister said, a day after the drug conviction of US basketball player Brittney Griner.

"We are ready to discuss this subject, but only within the framework of the (communication) channel established by presidents [Vladimir] Putin and [Joe] Biden," Sergei Lavrov told a press conference on a visit to Cambodia.

"If the Americans decide to once again resort to public diplomacy... that is their business and I would even say that it is their problem," Mr Lavrov said.

The Kremlin had previously warned the United States against resorting to "megaphone diplomacy" in the case of Griner, saying it could only derail efforts to secure a potential swap.

The Unites States has already made what Secretary of State Antony Blinken called a "substantial offer" to secure the release of Americans detained in Russia, including Griner and former Marine Paul Whelan.

A Russian court sentenced Griner to nine years in prison on drug charges yesterday.

Griner, who had been prescribed medical cannabis in the United States to relieve pain from chronic injuries, said she had made an honest mistake by inadvertently packing them as she rushed to make her flight.

She pled guilty to the changes against her but insisted that she did not intend to break Russian law.

Cannabis is illegal in Russia for both medicinal and recreational purposes.

Her sentencing could now pave the way for a US-Russia prisoner swap that would include the 31-year-old athlete and a prolific Russian arms dealer.

"I love my family," Griner told journalists after the ruling she was led away by members of Russia's law enforcement.

Her defence team told reporters the athlete - known as BG to her friends and fans - was "very upset" and "very stressed".

President Biden immediately released a statement, calling the Russian court's sentencing of Griner "unacceptable".

"Russia is wrongfully detaining Brittney," Mr Biden said in the statement.

"It's unacceptable and I call on Russia to release her immediately so she can be with her wife, loved ones, friends and teammates."

The US president reiterated that he would "work tirelessly and pursue every possible avenue" to repatriate Griner.

White House national security spokesperson John Kirby said after Griner's sentencing that the United States had made Russia a serious proposal.

"We urge them to accept it," he said. "They should have accepted it weeks ago when we first made it."

Mr Kirby did not provide further detail on the US proposal.