President Joe Biden is “disturbed” by reports of the declining health of imprisoned Russian opposition leader Alexei Navalny and is calling for his immediate release, according to the White House.

“We urge Russian authorities to take all necessary actions to ensure his safety and health,” White House press secretary Jen Psaki told reporters Wednesday. “We consider Mr. Navalny’s imprisonment on trumped-up charges to be politically motivated and a gross injustice.”

Navalny, a fierce critic of Russian President Vladimir Putin, is on a hunger strike in protest of the poor medical care he’s received in the prison where he’s been held since January.

Psaki said the Biden administration is closely monitoring the situation.

Last month, Biden joined with the European Union in imposing sanctions on Russian officials and entities over the treatment of Navalny, who was previously poisoned and nearly died. He spent five months in Germany to recover and was quickly arrested upon his return to Russia.

Psaki’s remarks Wednesday reiterated the White House’s view that Putin and his allies are targeting Navalny because of his criticism of the ruling regime.

The Associated Press reported Wednesday that an attorney for Navalny said the activist has been diagnosed with a double spinal hernia and is losing feeling in both hands. He previously was said to be possibly suffering from tuberculosis.

This is a developing story and will be updated with more information when it becomes available.

Russian opposition leader Alexei Navalny addresses demonstrators during a rally in Moscow on July 20, 2019.
Maxim ZMEYEV / AFP/Getty Images