Russia's foreign ministry said on Friday that the United States should show restraint and wait for the results of the forensic medical examination before accusing Russia of Alexei Navalny's death, TASS reported.
The UN human rights office on Friday urged the Russian authorities to ensure that a credible investigation into the death of opposition leader Alexei Navalny in prison was carried out.
"If someone dies in the custody of the state, the presumption is that the state is responsible – a responsibility that can only be rebutted through an impartial, thorough and transparent investigation carried out by an independent body," UN Human Rights Office spokesperson Liz Throssell said.
"We urge the Russian authorities to ensure such a credible investigation is carried out."
Russia's Investigative Committee has launched a procedural probe into the death, the Investigative Committee said.
US accusations of Russian responsibility
US Vice President Kamala Harris said the death of Russian opposition politician Alexei Navalny in an Arctic penal colony on Friday, if confirmed, would be a further sign of the brutality of Russian President Vladimir Putin.
Reports of Navalny's death shook the annual Munich Security Conference where leaders are gathered to bolster unity against Russia's two-year-old invasion of Ukraine.
Harris voiced skepticism of Russia's official explanation that Nalvany died after a fall at the penal colony.
"Let us be clear, Russia is responsible," she said, adding that it would be "a further sign of Putin's brutality" of the death is confirmed.
Speaking before Harris, US Secretary of State Antony Blinken said that if reports of Navalny's death are accurate, they underscore Russia's "weakness and rot."
The United States was working to confirm the death, White House national security Jake Sullivan told NPR.
US President Joe Biden had warned Putin after meeting the Russian leader in Geneva in June 2021 that Russia would risk "devastating" consequences if Nalvany died in prison. Since then, US relations with Russia have been in a steep downturn over the Ukraine war.
Harris and Blinken attended the annual security gathering less than a week after Donald Trump, the frontrunner for the Republican presidential nomination, said he would not defend NATO allies who failed to spend enough on defense from a potential Russia invasion.
In her speech in Munich, Harris said the US would never retreat from its NATO obligations put in place after World War Two, contrasting Biden's approach to global engagement with Trump's isolationist views.
Biden is likely to face Trump in November in what looks like a tight rematch of their 2020 contest. Trump's NATO comments have shocked Europe and Trump-supporting Republicans in Congress are blocking aid for Ukraine's defense against Russia.
Harris is scheduled to meet US lawmakers, Ukrainian President Volodymyr Zelenskiy and German Chancellor Olaf Scholz.
Harris is likely to be watched for her ability to lead amid questions over Biden's age as he seeks a second term. He is 81 and Trump is 77, and they have accused each other of mental decline.
Russia's invasion of Ukraine has brought war to a continent that has spent decades trying to forge peace, underwritten by US security commitments to the NATO military alliance that Trump has threatened to jettison.
The Senate approved a $95.34 billion military aid package for Ukraine and other countries on Tuesday, but the funding may never be put up for a vote in the Republican-controlled House of Representative because of Trump's opposition.
US Secretary of State Antony Blinken met with Yulia Navalnaya at the Munich Security Conference on Friday and expressed his condolences if reports of the death of her husband, Russian opposition leader Alexei Navalny, are true, the State Department said.
Blinken "reiterated that Russia is responsible for his death," the department said.