Israeli officials revealed Monday that the Islamic Republic had stepped up its support for Lebanese Shiite terror group Hezbollah over the past few weeks.

According to a Channel 2 report Monday, Israel has observed an increase in Iran weapons shipments to Hezbollah members — in Lebanon and on the Syrian side of the Golan Heights. Iran has also sent weaponry to Hamas rulers in Gaza and is even attempting to arm Hamas members in the West Bank, the report said.

“Israel warns: Iran is acting in recent days and weeks to prepare and arm Hezbollah for conflict with Israel, on a large scale,” Channel 2’s diplomatic correspondent Udi Segal tweeted later Monday.

The TV report said Israel was alarmed that the sanctions relief Iran would enjoy if it reaches a deal on its nuclear program would free up “billions of dollars” for further such weapons shipments, and for Iranian support for terrorism. The TV report said the officials added that it was “hard to see” how the deal, so firmly backed by the US, could help the interests of Israel and other US allies.

Israel expressed alarm over Russian President Vladimir Putin’s announcement earlier Monday that he was lifting the block on the transfer of the controversial weapons system to Tehran, against which both the US and Israel have lobbied hard.

A senior Iranian official on Monday hailed Russia’s decision to lift the ban as a step towards “lasting security” in the region.

“The development of bilateral cooperation [with Russia] and with neighboring countries in various fields can be very effective for lasting stability and security in the region,” Iranian Defense Minister Hossein Dehghan said, quoted by state news agency IRNA.

A senior Israeli official told Haaretz on Monday night that the Kremlin briefed Israel on its decision a short while before announcing the move. The official said Israel is worried components of the air-defense system will be transferred to Syria and Hezbollah, seriously hamstringing the air force’s ability to dominate the skies over Lebanon or Syria.

Lavrov said Monday that the advanced S-300 air-defense system set to be delivered to Iran was “purely defensive,” and posed no threat to Israel.

The system won’t “threaten the security of any state in the region, including, of course, Israel,” Lavrov said, according to Interfax, quoted by Bloomberg News.

Lavrov said Putin’s move to lift the block on transferring the weapon system was done after the nuclear agreement this month between world powers and Tehran made the self-imposed embargo unnecessary.

He added that Russia did not want to continue outlaying money to prevent the deal between Russia and Iran and hinted that Moscow was unhappy with international pressure to quash the sale.

“We could not have disregarded the commercial and reputation aspect. As you know, we bear serious financial outlays in connection with the suspension of the contract, and we do not deem such a position necessary any longer,” Lavrov said, according to Interfax.

Tehran filed a $4-billion lawsuit in 2010 against a Russian defense exporter for holding up the $800-million deal.

Meanwhile, US Secretary of State John Kerry called Moscow on Monday to raise the US’s objections over the air-defense missile systems deal with Iran.

The White House said Kerry made the US opposition clear in a phone call to Lavrov.

White House press secretary Josh Earnest indicated the move could endanger plans to ultimately lift sanctions on Iran as part of a final nuclear deal. He said unity and coordination with nations like Russia is critical to the success of the negotiations.

The Pentagon also expressed concern about the move, saying it was “unhelpful.

“Our opposition to these sales is long and public. We believe it’s unhelpful,” Pentagon Spokesman Colonel Steve Warren told reporters.

“We are raising that through the appropriate diplomatic channels,” he said.

Israel’s Intelligence Minister Yuval Steinitz also slammed Russia’s move, linking it to Iran’s newfound legitimacy following the Lausanne agreement this month with the P5+1 world powers.

“Even as Iran disavows article after article in the framework agreement that was announced last week, the international community is beginning to ease restrictions on it,” Steinitz said in a statement released Monday.

“This is the direct result of the legitimacy that Iran is receiving from the nuclear deal being made with it. This also proves that the economic momentum in Iran that will come in the wake of the lifting of the sanctions will be exploited for armaments and not used for the welfare of the Iranian people. Instead of demanding that Iran desist from the terrorist activity that it is carrying out in the Middle East and throughout the world, it is being allowed to arm itself with advanced weapons that will only increase its aggression,” he charged.

Israeli officials said supply of the system to Iran could prevent any military strike on Iran’s nuclear facilities, Channel 2 news reported. The officials said the supply, if it goes ahead, would change the balance of power in the region. The TV report also cited unnamed American officials responding with concern to the news.

Russian President Vladimir Putin and Iranian Foreign Minister Mohammad Javad Zarif during a meeting in the Kremlin in Moscow, Russia, on January 16, 2014. (photo credit: AP/Sergei Karpukhin, Pool)

Russian President Vladimir Putin (right) and Iranian Foreign Minister Mohammad Javad Zarif (left) during a meeting in the Kremlin in Moscow, Russia, on January 16, 2014 (photo credit: AP/Sergei Karpukhin, Pool)

A decree signed by Putin removes a ban on “the shipment from Russia to Iran” of the S-300 missiles, the Kremlin said in a statement earlier Monday.

Russia signed a 2007 contract to sell Tehran the S-300 system, but the weaponry was never delivered amid strong objections by the United States and Israel.

Moscow blocked deliveries of the surface-to-air missiles to Tehran in 2010 after the United Nations slapped sanctions on Iran over its nuclear program barring hi-tech weapons sales.

The decision to lift the delivery freeze comes after Tehran and international powers, including Russia, made a major breakthrough this month by agreeing to an outline deal aimed at curbing Iran’s nuclear program.

The Lausanne framework marked a crucial advance in a 12-year standoff between Iran and the West, which disputes Tehran’s denial that it is seeking to build a nuclear bomb. However, Israeli officials, led by Prime Minister Benjamin Netanyahu, have strongly condemned the deal for placing inadequate limitations on Iran’s ability to research and produce nuclear weapons.

Global powers must resolve a series of difficult technical issues by a June 30 deadline for a final deal, including the steps for lifting global sanctions imposed on Iran, and lingering questions over the possible military dimensions of its nuclear program.

Despite the dispute over the S-300 missiles, Moscow and Iran have remained on good terms, with Russia agreeing to build new nuclear reactors for Tehran and both sides supporting President Bashar al-Assad in Syria.

The S-300, developed by the Soviet Union in 1979, is a series of Russian long-range surface-to-air missile systems produced by NPO Almaz. The S-300 system was constructed for the Soviet Air Defense Forces in order to defend against aircraft and cruise missiles. Subsequent variations on the model were developed to intercept ballistic missiles.

AFP contributed to this report.