Lithuania's main airport reopened on Sunday after an hours-long closure due to a suspected "series of balloons", the latest such incident to disrupt flights in a European city.

Airports in Germany, Denmark, Norway and Poland have recently suspended flights due to unidentified drones, while Romania and Estonia have pointed the finger at Russia, which has brushed off the allegations.

Vilnius airport said it had received official information at 10:16 pm (1916 GMT) on Saturday that "air traffic is being temporarily suspended".

"According to our information, the decision was made due to a possible series of balloons heading toward Vilnius Airport," it said on Facebook.

The statement did not say where the purported balloons had come from.

The airport said later that its airspace had reopened at 4:50 am.

The shutdown affected at least 10 flights, with several planes -- including from London, Frankfurt and Vienna -- rerouted to the Latvian capital Riga.

One from Copenhagen was forced to turn back, while a scheduled departure to Helsinki was cancelled, Vilnius airport said.

"Other departures may also be delayed or cancelled," the airport warned.

The incident came after drone sightings this week caused Munich airport to shut down twice in as many days.

Flights from the German city gradually resumed on Saturday after travel disruptions affecting more than 6,500 passengers, the operator said.