The first batch of the advanced Yakhont cruise missiles, which are equipped with advanced radar systems, have arrived in Syria, Syrian President Bashar al-Assad confirmed in an interview with Lebanese television.

"Syria has received the first shipment of Russian anti-aircraft S-300 rockets," Hezbollah-linked Al-Manar TV quoted Assad as saying in an interview due to be broadcast later on Thursday. "The rest of the shipment will arrive soon."

Russia reportedly proceeded with the sale disregarding requests from the U.S. and its allies to stop arms sales to the regime, undermining efforts to bring peace to the region.

In the interview, Assad also threatened to retaliate should Israel strike in Syria. However, an Israeli official, on condition of anonymity, told Reuters that it has no information about the reports that Syria received S-300 missiles.

"I have no information beyond what has been reported, which we are looking into," he said.

Israel's Defense Minister Moshe Ya’alon told The Jerusalem Post: “Clearly this move is a threat to us," adding that Israel "will know what to do," when the missiles are delivered.

The powerful missile systems, nicknamed “ship killers,” can help Assad’s government counter any international force that might send reinforcements or supplies to Syrian rebels. The IBTimes, on May 17, reported that Russia had shipped the anti–defense system to Syria.

Russia's Foreign Minister Sergei Lavrov defended the arms sale claiming that the missiles are defensive systems. Russia, one of Syria’s strongest allies has been shipping advanced cruise missiles and other arms, citing a contractual obligation it has with the regime. According to a New York Times report earlier this month, Syria placed orders for the S-300 anti-ship missiles to Russia in 2007, and Moscow supplied the first batch of missile systems in 2011.

Moscow’s continuing display of commitment to Assad's regime is a significant concern to the U.S. and international forces as it could embolden Assad to prevail over the opposition by using military force.

The report of the Russian shipment comes as Washington and Moscow plan to convene an international conference to de-escalate the armed conflict in Syria. The conference, scheduled to take place in June, is expected to include representatives of the Syrian government and opposition forces, according to the Times report.