Shocking Photo: Jailed Putin Enemy Alexei Navalny Looks Gaunt Behind Bars, Loses 18 Pounds In 2 Weeks From Mystery Ailment

Kremlin dissident Alexei Navalny looked gaunt and worrisomely thin in a new photo captured behind bars amid fears he is being poisoned, RadarOnline.com has learned.

A spokesperson for Russia's imprisoned opposition leader and well-known Vladimir Putin detractor said that Navalny, 46, shed nearly 18 pounds in just over two weeks after falling ill.

Last Friday, he was removed from his punishment cell after 15 days and put in a conventional cell. It was allegedly the 13th time Navalny had been placed in a punishment cell amid his stint at the maximum-security penal colony at Melekhovo.

"The lawyer says that an ambulance was called for [Alexei] on the night of Friday to Saturday because of an acute stomach pain. No one is treating him and they are not even telling him the diagnosis," ​​Kira Yarmysh wrote in an update.

It was claimed that when Navalny asked for clarification on his ailment, "the prison doctor mockingly answers that it is just spring and everyone has exacerbations."

"We do not rule out that all this time in prison he could have been poisoned with something to make his health deteriorate slowly but steadily," added Yarmysh.

Yarmish shared that his "health and conditions worsen every day."

Navalny is currently serving combined sentences of more than 11 years on fraud and contempt of court charges. He expressed that it was an alleged attempt to silence him as the charges were condemned by critics as politically-motivated.

Anna Veduta, a Washington, D.C.-based vice president of Navalny's Anti-Corruption Foundation, told the Associated Press they believe "he is slowly being administered low doses of poison" in pills he is being given without identification.

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German government spokesperson Christiane Hoffmann said they have been made aware of Navalny's worsening health and are taking it "with great concern."

She stated that Berlin wants "the inhuman treatment that he is apparently suffering in prison to be lifted."