Wizz Air has announced it will suspend flights to the Moldovan capital, Chisinau, over airspace safety worries.
The flights will stop on 14 March, the company announced on Monday.
Moldovan foreign minister Nicu Popescu said his country was prepared for what he called a "full spectrum of threats", with fears Russia could intensify attempts to destabilise the country that has already been reeling from the war in its neighbour Ukraine.
In a statement, Wizz Air said: "Safety of the passengers and crew remain Wizz Air's number one priority.
"Following the recent developments in Moldova and the elevated, but not imminent, risk in the country's airspace, Wizz Air has made the difficult but responsible decision to suspend all flights to Chisinau from the 14th of March."
The budget airline said it would provide extra flights to and from the Romanian city of Iasi, which lies close to the Moldovan border.
Flights to Chisinau would be reallocated to Iasi from other destinations in Wizz Air's network, with more planes travelling from major European cities like Barcelona, Milan and London.
Flights from Chisinau to Budapest and Prague would not be replaced.
The Moldovan government said on its official Telegram channel: "After analysing the risks, government agencies have determined that flights in the national airspace can be carried out safely by following a number of procedures, and they regret Wizz Air's sudden decision."
The country's civil aviation authority and the ministry of infrastructure and regional development had been in "constant cooperation" with Wizz Air representatives and informed them of the procedures in place to ensure aviation security, the government added.
The aviation authority said it would take "all necessary actions" to return Wizz Air to Chisinau airport as soon as possible, and to attract other low-cost airlines.