In an apparent escalation of a dispute over the purchase of an air defense system, Iran filed suit against the Russian Federation with the International Court of Arbitration in Paris, hoping to either force Moscow to sell the military hardware to Tehran after all or pay reparations.

The Russians reneged on an agreement to sell surface to air missile systems to Iran last year after international sanctions prohibited arms sales to Iran. The country is suspected of developing nuclear weapons in violation of its obligations under the 1968 nonproliferation treaty.

Russian president Dmitri Medvedev stopped defense contractor Almaz-Antey from selling the S-300 system in 2010 and banned the sale of virtually all military hardware to the Islamic Republic along with it, implying a shift in Russian policy away from Iran with which it had previously cultivated relations and shared nuclear technology.

Dmitri Gorenburg speculated here last year that the decision was been made in order to remove roadblocks to the Russian purchase of sensitive military technologies from the West, including the Mistral helicopter carrier from France and unmanned drone aircraft from Israel.

Gorenburg suspected that the Russians might have envisioned the S-300 as a potential bargaining chip from the start, to be used against the United States in the event of bilateral discord. Canceling the deal would have been a gesture of goodwill toward the West.

Publicly, Moscow has cited United Nations sanctions as reason to cancel the weapons sale. The Iranians insist that existing sanctions do not cover the S-300 however but only prohibit trade in conventional weapon systems, including tanks and warplanes.

The S-300 system is important to Iran as its deployment could hinder Israel’s ability to conduct airstrikes against suspected nuclear sites in the country. Israel unilaterally destroyed nuclear facilities under construction in Iraq and Syria in 1981 and 2007 respectively and has repeatedly threatened to launch military action if Tehran comes close to finalizing a nuclear weapon.