Russia will complete early-stage trials on a second potential COVID-19 vaccine, produced by the Vector Institute, on Sept. 30, the RIA news agency cited Russia's consumer health safety watchdog as saying on Monday.

The country announced last month that its first vaccine, named "Sputnik V" after the Soviet-era satellite that was the first launched into space in 1957, had already received approval.

This has raised concerns among Western scientists over a lack of safety data, with some warning that moving too quickly on a vaccine could be dangerous.

Russia has denounced such criticism as an attempt to undermine Moscow's research.