Russian opposition leader Alexei Navalny has suffered back pains and leg problems in prison, his lawyer said.

The lawyer, Olga Mikhailova, said Mr Navalny’s condition has notably deteriorated in recent days.

“He’s suffering strong pains in his back and his right leg.

“He’s feeling numbness in his right lower leg,” Ms Mikhailova said outside the prison in remarks carried by independent Dozhd TV.

“His right leg is in terrible shape.”

The 44-year-old Mr Navalny, who is President Vladimir Putin’s most outspoken opponent, was arrested on January 17 upon his return from Germany, where he spent five months recovering from a nerve-agent poisoning that he blames on the Kremlin.

Russian authorities have rejected the accusation.

Ms Mikhailova said Mr Navalny was taken to a hospital outside prison on Wednesday for magnetic resonance tomography but was not given the results.

She said Mr Navalny has received pills and ointment for his pain, but prison authorities refused to accept medicines that lawyers brought to him.

Ms Mikhailova said Mr Navalny had experienced back pain for four weeks, but prison officials also would not permit a visit by his doctor.

The lawyer argued that authorities should transfer Mr Navalny to Moscow so he could get better treatment.

Earlier this month, Mr Navalny was moved to a prison colony in Pokrov in the Vladimir region, 53 miles east of Moscow.

The facility stands out among Russian penitentiaries for its particularly strict regime that includes routines like standing at attention for hours.

Russia’s Federal Penitentiary Service said earlier that Mr Navalny had undergone medical check-ups the previous day, describing his condition as “stable and satisfactory”.

Last month, Mr Navalny was sentenced to 2 1/2 years in prison for violating the terms of his probation while convalescing in Germany.

The sentence stems from a 2014 embezzlement conviction that Mr Navalny has rejected as fabricated — and which the European Сourt of Human Rights has ruled to be unlawful.

Russian officials have rejected demands from the United States and the European Union to free Mr Navalny and stop the crackdown on his supporters.