DUBLIN, IRELANDAircraft leasing companies around the world are ending hundreds of aircraft leases with Russian airline operators following Western sanctions over the invasion of Ukraine.

Dublin-based AerCap, the world's biggest lessor, said on Monday it would cease leasing agreements with Russian airlines, while Singapore-based BOC Aviation said most of its leases in Russia would now have to be terminated by March 28.

Russian airline operators have 980 passenger jets in service, of which 777 are leased from lessors. 515 of these aircraft are rented from foreign companies mainly based in Ireland.

AerCap, which has the largest exposure to Russia and Ukraine with 152 planes 5% of its fleet was leased in Russia as of December 31.

British ACC Aviation Vice President Viktor Berta said the repatriation process of leased aircraft could be challenging if Russian aviation authorities and airlines don't cooperate with lessors.

It could also take time for personnel to travel to Russia to repossess the aircraft due to the airspace closures, he added.

Avolon, another Dublin-based lessor and the world's second-biggest leasing company, has fewer than 20 jetliners in Russia and one or two in Ukraine.

Avolon stated that it was concerned that sanctions on international payment transfers through SWIFT could be disrupted, making it difficult for airlines to pay their bills.

Lessor BOC said it had 18 planes representing 4.5% of its owned fleet based in Russia, placed with Aeroflot subsidiary Pobeda as well as Ural Airlines, S7 Airlines, and AirBridgeCargo Airlines. It also has an aircraft in its managed fleet on lease to Rossiya Airlines.

"Our policy is to fully comply with all laws applicable to our business," the lessor said in a statement. "The practical consequences of the new EU sanctions are complex and at present, we are unable to provide further information."

Dubai Aerospace Enterprise (DAE) has at least three Russian airline customers, including Aeroflot, according to its website.

Novus Aviation Capital Co-Chief Executive Mounir Kuzbari said the firm had no aircraft in Russia, but that mass cancellation of leases in Russia could hit global lease rates and aircraft values.

Other foreign leasing companies with aircraft in Russia are SMBC Aviation Capital, Air Lease Corp, and Aviation Capital Group.