Russian President Vladimir Putin on Sunday blamed Ukrainian secret services for the huge blast a day earlier that ripped through Russia's Crimea bridge, which he described as a "terrorist act".

"The authors, perpetrators and sponsors are the Ukrainian secret services," Putin said during a meeting with the head of the investigation committee, according to a video shared by the Kremlin.

"There is no doubt this is a terrorist act aimed at destroying critical Russian civilian infrastructure," Putin added.

A truck bomb on Saturday ignited a massive fire on the road and rail link between Russia and the annexed Crimea peninsula, killing three people.

Ukraine has not claimed responsibility for the explosion.

The bridge is logistically crucial for Moscow -- a vital transport link for carrying military equipment to Russian soldiers fighting in Ukraine.

It is also hugely symbolic. Putin personally inaugurated the structure in 2018 -- even driving a truck across it -- and Moscow had maintained the link was safe despite the fighting.