The team of late Russian opposition politician Alexei Navalny said Monday that a deal to free him as part of a prisoner swap had nearly been reached when he died in prison.

The 47-year-old Kremlin critic died on February 16 after spending more than three years behind bars, prompting outrage and condemnation from Western leaders and his supporters.

Russian President Vladimir Putin "was offered to exchange FSB officer and killer Vadim Krasikov, who is serving time for murder in Berlin, for two American citizens and Alexei Navalny," ally Maria Pevchikh said.

"I have received confirmation that negotiations were underway and were at the final stage" after two years of talks between Moscow, Washington and Berlin, she added.

"Navalny was supposed to be released in the coming days," she added.

Asked about the claims during a regular briefing, the German government spokeswoman declined to comment. 

Krasikov is serving a life sentence in Germany for the 2019 killing of former separatist commander Zelimkhan Khangoshvili in a Berlin park, which German authorities say was ordered by Russian intelligence services.

Washington has accused Moscow of arresting American citizens on baseless charges to use them as bargaining chips to secure the release of Russians convicted abroad.

Among US citizens detained in Russia are former US marine Paul Whelan and Wall Street Journal reporter Evan Gershkovich, both accused of espionage.