The US yesterday said it was “deeply concerned” by Navalny’s team saying they have had no access to him for almost a week and reports that he was taken out of the prison where he has been held for months.

“We are talking about a prisoner who was found guilty by the law and is serving the prison sentence he received. Any interference, including from the US, is unacceptable,” Kremlin spokesman Dmitry Peskov told reporters.

The US also said that Navalny should be “released immediately” and that “he should never have been jailed in the first place.”

Navalny’s team said the politician – serving a 19-year sentence – had missed several court hearings and that lawyers were told he was removed from his prison.

“Today, Alexei was again not taken to court via video link,” his exiled spokesman Kira Yarmysh said on social media today.

“An employee of the IK-6 (prison colony) stated that Alexey ‘left the colony’ but apparently nobody knows where he was taken,” she said.

It was the seventh day that Navalny’s allies said they had no contact with him.

A court this summer prolonged Navalny’s sentence to 19 years and also ruled that he be moved to a harsher – “special regime” – prison.

Navalny’s allies linked his disappearance and possible transfer to a harsher prison with President Vladimir Putin’s announcement that he plans to extend his long rule by running for a fifth presidential term in March.

Russia’s huge prison system often takes weeks – or longer – to move prisoners between far-flung facilities by rail.