A close ally of jailed Russian opposition leader Alexei Navalny urged U.S. President Joe Biden to take punitive action against a wider group of associates of President Vladimir Putin, saying current sanctions aren’t sufficient to stop the Kremlin from cracking down on political opponents and violating human rights.

"Existing sanctions don’t reach enough of the right people,” Vladimir Ashurkov wrote in a letter to Biden posted on his Facebook page on Saturday. He listed 35 people, including billionaires Roman Abramovich and Alisher Usmanov, senior staffers of Putin’s administration, and the heads of several state companies who Navalny says should be targeted.

"Anything less will fail to make the regime change its behavior,” Ashurkov wrote. "The West must sanction the decision makers who have made it national policy to rig elections, steal from the budget, and poison.” Navalny and his allies also want the U.S. to sanction those who hold their money.