Israeli Prime Minister Benjamin Netanyahu's office declined on Wednesday to comment on the first delivery of Russian-made S-300 air defense systems to Iran.
The first batch of surface-to-air missiles capable of downing jets was delivered to Iran on Monday, according to Russian Deputy Prime Minister Dmitry Rogozin.
"We do not comment on this," Netanyahu's spokeswoman told RIA Novosti.
Russia and Iran signed a $900-million contract in 2007 amid opposition from Israel and the United States. The deal was suspended after the UN Security Council imposed sanctions on Iran in mid-2010.
In April 2015, Russia resumed talks on S-300 deliveries following a framework agreement on a landmark pact that aimed to ensure the peaceful nature of Tehran's nuclear program.
Israel, in turn, criticized Russia's decision to go ahead with arms deliveries to Iran, saying that it would further destabilize the region.