Russia has classified data which "proved Vladimir Putin had been treated for cancer", it has been claimed.
A loophole previously allowed investigative journalists to show that the dictator was constantly accompanied by a top thyroid cancer specialist and other medics.
Revelations last April indicated surgeon Yevgeny Selivanov, of Moscow's Central Clinical Hospital, had flown to the Russian leader no less than 35 times in Black Sea resort Sochi.
The proof of Putinâs treatment by cancer doctors was deduced from the existence of contracts with the hospital - which were listed on a Russian public procurement website.
Now such details have been made top secret, preventing public knowledge of current and future contracts.
Earlier it was seen that Putin was accompanied by between six and 13 medical specialists on his trips.
Medics were also seen to be on standby near his favourite officials residences outside Moscow, for example in Sochi and Valdai.
The report by Proekt media in April gave credence to rumours that Putin had suffered from cancer.
The medics appeared to be thyroid and ENT specialists.
The blocking of data of such contracts was revealed by Sirena, part of Radio Liberty.
The move is likely to increase speculation that the Kremlin is hiding the truth about Putinâs health during the war against Ukraine.
Symptoms of thyroid cancer include the appearance of a thick nodule in the thyroid area, hoarseness of voice, difficulty swallowing, pain in the neck and throat, enlarged lymph nodes in the neck and a dry cough, scratchy or scratchy feeling in the throat or behind the sternum.
There have also been claims that Putin is suffering from abdominal cancer and other ailments.
Further, there have been suggestions that drugs to treat his cancer may have distorted his mind when he launched the war in Ukraine.
The Kremlin insists that Putin is healthy.
Among the medics named as treating Putin were Dr Dmitry Verbovoy, an expert in acute illnesses, injuries and poisonings.
Another was Dr Konstantin Sim, an orthopaedic traumatologist, possibly helping with ice hockey injuries, ENT doctor Alexei Shcheglov and infectious disease specialist Yaroslav Protasenko.
He was also seen by neurosurgeons from the Central Clinical Hospital, led by department head Oleg Myshkin and Dr Elena Rastrusina, plus a resuscitator Dr Pavel Sharikov, and head nurse Lyudmila Kadenkova.
A rehabilitation specialist was also involved, Dr Mikhail Tsykunov.
In July 2020, Putin met with the head of the National Medical Research Center for Endocrinology Ivan Dedov.
