MOSCOW — Russia said Monday it would equip Syria with sophisticated air defense systems, a move that could worsen a rift with Israel by limiting its ability to bomb across its northern border.

Defense Minister Sergei Shoigu said Moscow would send Russia’s powerful S-300 ground-to-air missile systems to Syria, a longtime ally, in the next two weeks. Israel, which has repeatedly bombed Iranian targets in Syria, has long opposed such deliveries, and Russia up to now has refrained from supplying the weapons.

But the downing last week of a Russian reconnaissance plane with 15 service members aboard changed the dynamic. The plane was shot down by a Syrian missile, but Russia faulted Israel for the crash because an Israeli fighter jet allegedly had used the Russian plane as a screen against Syria’s air defenses.

Israel, by contrast, said that its air force had not violated any agreements with Russia and that Israeli jets had already returned to Israeli airspace when the missiles were launched. The crash was one of the deadliest incidents for regular Russian service members in the Syrian war.

“Today, the situation has changed, for no fault of ours,” Shoigu said in a televised statement Monday announcing the S-300 deliveries.

Shoigu said Russia also will jam military aircraft communications in the airspace next to Syria over the Mediterranean Sea while upgrading Syria’s air defense command systems.

Russian officials did not, however, signal a desire to fundamentally alter the relationship with Israel — a key element of the Kremlin’s push to build its influence in the Middle East. Russian President Vladimir Putin told Israeli Prime Minister Benjamin Netanyahu in a phone call Monday that the missile delivery was meant primarily to “counter any potential threat to the lives of Russian service members,” the Kremlin said.

Russia released an animation on Sept. 23, which contradicts the Israeli account of an incident in which a Russian military plane was downed by Syrian forces. (Russian Ministry of Defense via Storyful)

Netanyahu told Putin that the transfer of advanced military systems to “irresponsible hands” would increase the dangers in the region and that Israel would continue to defend its security and interests, according to a statement from his office. The leaders agreed to continue dialogue, and Netanyahu reiterated his condolences over the deaths of the Russian soldiers, it said.

The flare-up in tensions between Russia and Israel marks a turnabout after months of personal diplomacy between Putin and Netanyahu, in which the two leaders forged a close relationship. A Russian Defense Ministry spokesman described Israel’s actions leading to the shoot-down last week as “ungrateful,” given what he said were Russian accommodations of Israeli requests, including relocating Iranian troops from the border of the Israeli-occupied Golan Heights and providing Russian patrols in the area.

“You know that Israel and the Russian Federation have quite advanced relations,” Kremlin spokesman Dmitry Peskov said Monday. “Everything had worked right up until the tragedy that occurred recently.”

Putin informed Syrian President Bashar al-Assad about the missile delivery in a phone call Monday, according to a statement issued by Syria’s presidency. Although Putin had sought last week to tamp down tensions over the downing of the plane, calling the incident an “accident,” he told Assad he “held Israel responsible” for the deaths of the 15 Russian service members, the statement said.

If delivered, the S-300s would further shift the military balance in Syria in favor of Assad and of Iran and its allied militia, Hezbollah. Iran and Hezbollah have vowed to maintain a presence in Syria, over Israel’s objections, even though the war is winding down.

Although Russia suggested its immediate goal in supplying the missiles would be to protect Russian aircraft from accidental shoot-downs, the S-300s would also give Syria enhanced capacity to take on any of the other countries flying sorties in its crowded skies, including the United States and its allies in a coalition against the Islamic State.

Israel has fiercely lobbied Russia against providing Syria with the S-300 systems. Israel flies missions with relative ease over Syria, given the latter’s largely antiquated air defenses, and Israeli officials recently admitted that more than 200 bombing raids have been carried out by Israeli warplanes inside Syria over the past two years.

Israel says it is determined to stop Iran, a longtime foe that has sent forces to back Assad, from becoming entrenched near Israel’s northern border. Israel also wants to prevent the transfer of advanced missile systems to Iranian proxies, including Hezbollah, a militant Shiite group based in neighboring Lebanon.

A flurry of shuttle diplomacy by Israeli officials to Russia appeared to be paying off in May, when Russian officials said just days after a visit by Netanyahu that they did not plan to sell the S-300 system to Syria. More broadly, Israel also sees Russia as key to protecting its interests in Syria by preventing a buildup of Iranian-linked bases and infrastructure.

The deterioration in relations between Russia and Israel, along with the promised transfer of the S-300 system, complicates Israel’s efforts to contain Iranian influence.

“For Israel, it may have to balance more carefully the desire to limit the production of advanced missiles and prevent their transfer, with essentially direct confrontation with Syria,” said Ofer Zalzberg, a Jerusalem-based analyst with the International Crisis Group. “This high-precision campaign it has been carrying out will become more difficult.”

The transfer may make Israel more cautious in the short term, Zalzberg said. “I think they will become more risk-averse, though at the same time try and signal the opposite,” he said. “Israel will try and preserve its ability to act in Syria, which means maintaining relations with Moscow.”

Morris reported from Jerusalem. Sly reported from Beirut.