Russia and China signed a $2.5 billion deal on the delivery of 24 Sukhoi Su-35s in 2015, making it the first foreign buyer of the fourth-generation multirole air superiority fighter. The United States imposed sanctions on the Chinese military last September for buying 10 Su-35s in 2017 and missile systems in 2018 from Russia.

Russia has completed the delivery of Su-35 combat aircraft to China in defiance of U.S. sanctions, Russia’s military and technical cooperation agency told state media Tuesday.

“In compliance with the contract, all the Su-35 planes have been delivered to the foreign customer,” the Federal Service for Military and Technical Cooperation told the state-run TASS news agency.

The first batch of 10 Su-35s was delivered to Сhina in December 2016, followed by 10 more in December 2017, according to Tokyo-based The Diplomat news magazine. The last batch was expected to be delivered in December 2018.

The U.S. found China's Equipment Development Department (EDD), the branch of the Chinese military responsible for weapons and equipment, in breach of a sweeping U.S. sanctions law punishing Moscow for meddling in the 2016 U.S. election.

Reuters contributed reporting to this article.