A number of domestic flights headed for St Petersburg turned back. (Representational)
Russia's Pulkovo Airport in St. Petersburg temporarily suspended all flights on Tuesday morning before restarting them amid unconfirmed Russian media reports of an unidentified object such as a drone in the area.
The government of Russia's second city announced the closure on its official Telegram channel without providing a reason for the suspension.
Russian news agencies reported later on Tuesday that flights had resumed and that a temporary airspace ban within a 200-kilometre (124-mile) radius of Pulkovo had been lifted by 1200 local time (0900 GMT).
The RIA Novosti news agency had earlier reported, citing a source in the city's emergency services, that an unidentified object had been spotted, prompting the initial closure.
Unconfirmed media reports from two online Russian news outlets reported that fighter jets had been despatched to investigate. They later said that the jets had not found anything.
There was no official comment on what caused the disruption or on how the alleged unknown object was investigated.
Data from the FlightRadar24 website showed a number of flights headed for St Petersburg turning back to their destinations early on Tuesday, while the airspace closure also appeared to affect flights en route to the Russian exclave of Kaliningrad, which requires planes to fly over St. Petersburg.
By 1200 local time, flights had resumed flying towards St. Petersburg, the FlightRadar24 website showed.
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