MOSCOW (BLOOMBERG) - Russia will halt some international flights to keep rented planes out of the hands of foreign owners trying to take them back.

The order takes effect starting Sunday (March 6) and applies to airlines that have leased planes from foreign owners, the country's aviation regulator said on Saturday in a statement.

It cited "the high risk of Russian airlines' planes being held or seized abroad".

The move will give Aeroflot and other Russian carriers cover to hold on to hundreds of aircraft that, under European Union (EU) sanctions, must be returned to owners by March 28.

It will also isolate the country further, making it harder for citizens to travel internationally after a swath of countries closed airspace to Russian carriers in response to its invasion of Ukraine.

Aeroflot, Russia's flag carrier and its most prominent link to foreign destinations, said on Saturday that it will halt all international flights by March 8, the deadline for flights to return, Interfax reported.

Bigger headache

Foreign lessors are grappling with how to retrieve Boeing and Airbus aircraft worth billions of dollars after sanctions forced them to cancel contracts with Russian customers.

While the planes eventually may be retrieved, the Russian move on Saturday will make it harder to gain access to the aircraft. Analysts have said writedowns are likely.

Contingent insurance policies, maintenance reserves and letters of credit associated with the leases could reduce potential losses, Fitch Ratings said in a research note on Friday.

"The sanctions present significant logistical and operational challenges given the unique and rapidly evolving situation, meaning repossession of aircraft in Russia could prove more difficult," the ratings firm said.

The war and ensuing sanctions have ripped a hole what was, up until late last month, a tightly integrated global travel network.

Britain, EU, the US and Canada have closed their airspace to Russia. Russia has banned each of those, with the exception of the US, in return.

New EU sanctions ban the supply to Russia of "all goods and technology" linked to aircraft.

Follow The Straits Times' live coverage on the Ukraine crisis here.