Europe's drug regulator launched a review of Russia's Sputnik V coronavirus vaccine on Thursday, putting it on course to be the first non-Western jab used across the 27-nation EU.

Russia quickly said it was ready to provide jabs for 50 million Europeans as soon as the shot gets the green light from the Amsterdam-based European Medicines Agency (EMA).

Moscow has pushed Europe to follow the lead of dozens of countries around the world that have approved Sputnik, but Brussels has been wary the Kremlin will use the jab as a soft-power tool.

"EMA has started a rolling review of Sputnik V, a Covid-19 vaccine developed by Russia's Gamaleya National Centre of Epidemiology and Microbiology," the EMA said in a statement.

-The rolling review will continue until enough evidence is available for formal marketing authorisation application.-

The review follows clinical studies and lab tests which "indicate that Sputnik V triggers the production of antibodies and immune cells" that can protect against Covid-19, the EMA said.

The regulator added that it would "assess Sputnik V's compliance with the usual EU standards for effectiveness, safety and quality."

Russia and the EMA have sparred in recent weeks over Sputnik, with the vaccine's developers calling for the rolling review to start more quickly.

European leaders have meanwhile been warming to the idea of deploying Sputnik as the continent struggles with shortfalls of the three currently-authorised Western jabs.

They are the US-German Pfizer/BioNTech jab, US firm Moderna's shot, and the British-Swedish AstraZeneca/Oxford vaccine.

Sputnik's developers said the start of the rolling review was a "major step for (the) vaccine's approval for use in the EU."

-Following EMA approval, we would be able to provide vaccines for 50 million Europeans starting from June 2021- Kirill Dmitriyev, the head of the Russian Direct Investment Fund (RDIF), which developed Sputnik, said in a statement.

Fast-track procedure

Several EU member states including Germany and Spain have said recently they would be interested in Sputnik V if it was approved, while Hungary registered it on its own.

Concerns were initially raised about Sputnik after a fast-track procedure that saw it approved for use in Russia last August and deployed in December ahead of large-scale clinical trials.

The EU has also been cautious of using vaccines that could give Moscow or Beijing geopolitical influence.

European Commission chief Ursula von der Leyen said in February that she wondered why Moscow was so keen to offer millions of doses to the EU "while not sufficiently progressing in vaccinating their own people".

But pressure has grown since the Lancet medical journal published results in February showing Sputnik V to be 91.6 percent effective, based on third-phase trials with more than 20,000 volunteers.

The RDIF, which helped finance the development of Sputnik V, said Thursday that 42 countries have registered the vaccine.

The EMA said a decision on possible approval for Sputnik should "take less time than normal" due to work already done during the rolling review.

It has taken between two and four months for other Covid jabs to move from rolling review to EU authorisation.

One further hurdle could be the insistence of EU officials that Sputnik production sites outside the bloc would need to be inspected.

-They are not producing in Europe, so of course there should be an inspection process on the production sites- von der Leyen said last month.

Sputnik's developers said on Twitter that "we look forward to welcoming EMA inspectors at the Sputnik V facilities".

The EMA is set to give its decision on Johnson & Johnson's single-shot vaccine on March 11. Jabs by Novavax and CureVac are also under rolling review.