(JTA) — Russia’s foreign minister said his country will honor an agreement to provide the S-300 advanced air defense missile system to Syria.

Sergey Lavrov on Thursday told Russian State TV that Russia will “honor all our contractual obligations.” He confirmed that the contract with Russia has “not been delivered in full,” according to the Associated Press.

The Wall Street Journal reported last month that Israel had informed the United States of an imminent deal with Russia to sell the advanced ground-to-air missiles to Syria. Possession of S-300 missiles would significantly boost Syria’s ability to stave off intervention in its on-going two-year civil war, in which at least 93,000 people reportedly have been killed.

Information provided to Washington by Israel showed that Syria has been making payments on a 2010 agreement with Moscow to buy four S-300 batteries for $900 million, according to the Journal. The paper said the package included six launchers and 144 operational missiles, each with a range of 200 miles, with an initial shipment expected over the summer.

Western nations repeatedly have urged Russia to block the sale, which they argue could complicate any international intervention in the escalating civil war.

Russia until now has heeded U.S. and Israeli requests to delay delivery of the S-300 systems.