The Kremlin has never made any deals with Telegram boss Pavel Durov, Kremlin spokesman Dmitry Peskov said on Friday, adding that he was not aware of any meetings between the tech entrepreneur and Russian President Vladimir Putin.

A French judge put Russian-born Durov under formal investigation on Wednesday for suspected complicity in running an online platform that allows illicit transactions, child sex abuse images, drug trafficking and fraud.

Durov's lawyer said on Thursday it was "absurd" to suggest he should be held responsible for any crimes committed on the app.

"There were no negotiations between Durov and the Kremlin," Peskov told reporters. "And the fact that he visited Russia, well, he is a Russian citizen, he moves freely, so naturally he visited Russia.

"There were no deals between the Kremlin and Durov," Peskov said in response to further questions.

Peskov said that as far as he was aware, Putin and Durov had never met.

Russia, after years of pressure on Durov and his tech ventures, has rallied behind him, with Peskov this week saying that the case against him should not become political persecution.

Moscow tried and failed to block Telegram, which has almost 1 billion users, in 2018, and has demanded the platform hand over data in the past, something Durov says he refused to do.

The case has plunged Franco-Russian relations to new lows, according to Moscow, where some pro-Kremlin figures have accused Washington of being behind the detention of Durov, something Paris has denied.