A Boeing 737 operated by Russia's S7 Airlines, en route to Sochi, experienced a suspected cabin pressurization issue on Tuesday. The flight crew identified the problem and elected to return to Novosibirsk airport in Siberia for inspection.

Flightradar24, the civil aviation tracking website, reported the aircraft issued an emergency signal and circled Chulym, Novosibirsk Oblast, 5 to 6 times, likely to burn off fuel before landing safely. The number of passengers onboard is currently unknown.

An S7 Airlines Boeing 737 in 2010. Photo: Airliners

An S7 Airlines Boeing 737 in 2010. Photo: Airliners

S7 Airlines provided another aircraft for passengers to continue their journey to Sochi. Russian authorities are investigating the incident.

This incident follows Monday’s crash of an Angara Airlines An-24 passenger plane during an emergency landing in Russia's Far East, resulting in the deaths of all 49 people on board.

Huyen Le (Reuters, TASS)