President Vladimir Putin said on Tuesday that the shooting down of a Russian military plane near Syria’s seacoast was the result of a chain of tragic and chance circumstances.

Russia’s Defence Ministry said earlier that the aircraft was shot down by Syrian anti-aircraft systems, but accused Israel of indirectly causing the incident, saying Israeli jets nearby had put the Russian plane in the path of danger.

The ministry threatened to retaliate over what it called a hostile act.

Putin’s comments, made after talks with Hungary’s prime minister in Moscow, appeared to somewhat defuse the situation though he said Russia needed to look further into what happened.

“It looks most likely in this case that it was a chain of tragic chance events, because an Israeli aircraft did not shootdown our aircraft. But, without any doubt we need to seriously get to the bottom of what happened,” Putin told reporters.

Putin said Moscow’s response would aim at securing the safety of Russian military personnel in Syria’s complex civil war in which various outside powers have backed opposing sides.

“As for retaliatory measures, they will be aimed first and foremost at further ensuring the safety of our military personnel and facilities in Syria. And these will be steps that everyone will notice,” Putin said.

Russia’s Defence Ministry said the Il-20 reconnaissance aircraft, with 15 Russians on board, was downed by anti-aircraft guns of Moscow’s ally, Syria, in a “friendly fire” incident.

But the ministry said it held Israel responsible because, at the time of the incident, Israeli jets were attacking Syrian targets and had only given Moscow one minute’s warning, putting the Russian aircraft in danger of being caught in cross-fire.

“We view the actions of the Israeli military as hostile,”Russian Defence Ministry spokesman Igor Konashenkov told Russian state television. “As a result of the irresponsible actions of the Israeli military, 15 Russian service personnel perished.”

At a monthly UN Security Council meeting on Syria, US adviser on Syria, James Jeffrey, expressed “sorrow to our council partners Russia for the tragic loss of life …” “The unfortunate incident reminds us of the need to find a permanent, peaceful, and political resolution to the conflict.”

ISRAEL BLAMES ‘INACCURATE’ SYRIAN FIRE

In a statement the Israel Defense Forces (IDF) expressed sorrow at the deaths but blamed the Syrian government and its allies Iran and Hezbollah.

The IDF said the initial Israeli inquiry into the incident found “extensive and inaccurate” Syrian surface-to-air anti-aircraft fire “caused the Russian plane to be hit and downed”.

“The Syrian anti-air batteries fired indiscriminately and from what we understand, did not bother to ensure that no Russian planes were in the air,” the statement said.

It added that by the time the Russian plane was struck, the Israeli jets were already back in their own airspace.

The Russian plane was “not within the area of the operation” carried out by the Israeli jets, it said. An Israeli diplomatic source said Prime Minister Benjamin Netanyahu was expected to speak shortly with Putin. After the incident, Russian Defence Minister Sergei Shoigu told his Israeli counterpart, Avigdor Lieberman, that Moscow held Israel wholly responsible, Russian news agencies reported. Israel’s Foreign Ministry said its deputy ambassador in Moscow had been summoned to the Russian Foreign Ministry but gave no details of what was discussed.

The Russian Ministry said the meeting was to do with the loss of the Russian plane.