Plane-leasing giant AerCap Holdings NV said it will stop doing business with Russian airlines as sanctions tighten over the invasion of Ukraine, threatening to ground scores of jets at operators including Aeroflot PJSC.

The world’s No. 1 lessor, which is based in Dublin and listed in New York, is responding to broad measures against Russia and its companies imposed by the European Union, U.S. and other countries, it said in a statement Monday.

“AerCap intends to fully comply with all applicable sanctions, which will require us to cease our leasing activity with Russian airlines,” the company said. The lessor didn’t comment on whether it will seek to seize back its planes.

While only about 5% of the AerCap portfolio is affected, the move will impact a significant chunk of Russia’s jetliner fleet, amounting to 152 aircraft with a market value approaching $2.5 billion, according to analysis from IBA Group, which advises airlines, planemakers, banks and lessors.

Aercap shares slid 2.9% in premarket trading in New York. The stock was down 4% this year as of Friday’s close.

EU sanctions announced Sunday ban the supply of “all goods and technology” linked to aircraft, giving leasing firms the challenge of terminating contracts and recalling planes as the war continues to rage.

More than half of the active commercial fleet in Russia is leased, mostly from companies based abroad. AerCap has 96 planes with Aeroflot and 17 at its discount arm Pobeda, based on data from consultant Avitas.

Repossessions may already be taking place.

A European lessor is recalling three Boeing Co. 737 aircraft from Pobeda, Interfax reported, citing an unidentified source at the flag carrier. Russian media outlet RBC said that an Irish leasing firm seized a Pobeda 737 at Istanbul’s Havalimani airport, citing an unidentified Russian airline source.