Iran said it is sending officials to Russia to choose a substitute for the sophisticated long-range S-300 air defense missile system, which Russia said it would not deliver to Tehran.

Iran’s Fars news agency reported Tuesday that National Security and Foreign Policy Commission chair Alaeddin Boroujerdi met with Iran’s ambassador to Russia to discuss possible replacements for the S-300 system.

“A team from the defense ministry has left [for Russia] and another team is due to travel there again to discuss the issue,” the news agency quoted Defense Committee chairman Esmail Kosari as saying.

One possible substitute suggested by the news agency was the Antei-2500 system, which does not fall under sanctions imposed on Tehran and is geared for use by ground forces — unlike the S-300, which is geared towards use by missile defense forces.

In 2010, Russia called off the sale of five S-300 missile batteries to Iran as part of an agreement worth $800 million.

The two countries had signed the S-300 missile system deal in 2007, but it was canceled as part of UN Security Council sanctions against the Islamic Republic. The cancellation led to tensions between the two countries, including a $4 billion Iranian lawsuit against Russia.

In November, Iran announced it had inaugurated a missile production plant aimed at improving the country’s air defense capabilities.

Iranian Defense Minister Gen. Hossein Dehghan announced that the Sayyad-2 missile production facility would allow the Islamic Republic to hit helicopters, drones and other aerial targets at medium range. The solid fuel gives the missiles improved accuracy compared to liquid-fueled missiles, which make up the bulk of Iran’s air defense arsenal.

Dehghan said scientists have also completed research on another missile system named Talash, or effort.

A week later, Tehran said it successfully tested a new air defense system modeled after the US Hawk system during a drill in the country’s east. A senior Iranian official called the maneuvers a “slap” to America and Israel.

Earlier reports said the new surface-to-air system is named “Mersad,” or Ambush. It is capable of locking a flying object at a distance of 80 kilometers and can hit from 45 kilometers away, state TV said.

Tehran has been trying to set up a self-sufficient military program since 1992, putting an emphasis on air defense and naval power.

Israel and the West have expressed concern in the past over Iran obtaining the state-of-the-art anti-aircraft missiles, as they could severely affect the outcome of an airstrike against Iran’s nuclear reactors. Israel has also urged Russia not to sell the S-300 system to Syria, where it could impact Israel’s air supremacy relating to both Syria and Lebanon.

Israel and the US have not ruled out a military option against Iran’s suspect nuclear program, which the West fears intends to produce atomic weapons. Iran denies the charge, saying its nuclear program is for peaceful purposes only.