REUTERS -- Russia will begin the first shipment of its S-300 air defense missile systems to Iran in the coming days, Interfax news agency quoted a senior Russian diplomat as saying on Tuesday.

"I don't know if this will happen today, but they (S-300 missiles) will be loaded (for shipment to Iran)," the agency quoted Zamir Kabulov, a department chief at the Foreign Ministry, as saying.

On Sunday, the Israeli deputy air force chief said that Israel’s neighbors are buying arms on a scale that threatens its regional military superiority.

"There are countries here which have plans that are being actualized for arms deals in the hundreds of billions of dollars, for the most advanced Western weaponry and the most advanced Eastern weaponry," Brig. Gen. Tal Kelman told a conference to promote Israel’s purchase of the advanced U.S. fighter jet the F-35.

Kelman did not specify countries other than Iran, which the Israelis fear will use sanctions relief from last year’s nuclear agreement to build up its ballistic missile program and arm Islamist guerrillas like Lebanon’s Hezbollah militia.

This is a developing story. Stay tuned for more updates.