Russian President Vladimir Putin has blamed Ukraine for Saturday's explosion on a bridge connecting Crimea and Russia.

Putin made the remark during his meeting with the chairman of the Russian Investigative Committee on Sunday. The president said there is no doubt that the blast was "a terrorist act directed at the destruction of critically important civilian infrastructure of Russia."

He said the authors, perpetrators and those who ordered the explosion are the special services of Ukraine.

Officials in Kyiv have not directly stated whether they were involved in the explosion. But a major Ukrainian media outlet quoted sources as calling it a special operation carried out by Ukraine's intelligence agency.

The bridge had been a symbol of Russia's control of Crimea, which Moscow annexed in 2014. Four years later, Putin drove a truck across the bridge when the construction was complete.