This file photo taken on Oct. 2, 2018 shows British former Foreign Secretary Boris Johnson speaks at a Conservative home fringe meeting on day three of the Conservatives Party annual conference 2018 in Birmingham, Britain. (Xinhua/Han Yan)

MOSCOW, July 24 (Xinhua) -- Russian President Vladimir Putin sent a message of congratulations to new British Prime Minister Boris Johnson on Wednesday, the Kremlin said in a press release.

"Developing relations in a variety of areas would be for the benefit of our countries and peoples," Putin said in the message, wishing Johnson success in his post.

Earlier in the day, newly-elected Conservative Party leader Johnson took office as the British prime minister amid rising uncertainties of Brexit.

Moscow-London ties have been strained since March 2018, when former Russian intelligence officer Sergei Skripal and his daughter were allegedly poisoned in Britain's southwestern city of Salisbury, an incident that sparked a diplomatic war between Russia and several Western countries.