Syrian regime missile defence systems last week shot down a Russian military plane, killing all 15 people on board.

Russian air defence system missile system Antey 2500, or S-300 VM, on display at the opening of the MAKS Air Show in Zhukovsky outside Moscow on Tuesday, Aug. 27, 2013.
Russian air defence system missile system Antey 2500, or S-300 VM, on display at the opening of the MAKS Air Show in Zhukovsky outside Moscow on Tuesday, Aug. 27, 2013. (AP)

Russia announced on Monday that it will supply the Syrian government with modern S-300 missile defence systems following last week's downing of a Russian plane by Syria, that send regional tensions over the war-torn country soaring.

The Russian military aircraft was downed by Syrian regime missile defence systems, killing all 15 people on board. 

Russia laid the blame squarely on Israel, saying that its fighter jets had pushed the Russian plane into the line of Syria's fire.

Shortly before the downing, Israeli strikes had hit targets inside Syria, reportedly preventing an arms shipment going to Iranian-backed Hezbollah group.

Russia launched its campaign in Syria to support the Assad regime in 2015 and though the involvement turned the tide of war in favor of regime forces, Moscow has since played a careful balancing act, maintaining good ties both with Iran and Israel.

For its part, Israel is wary of Iran's growing influence in Syria, bringing its archenemy closer to its borders.

Last week's downing has put Russia's relationship with Israel to a test.

President Vladimir Putin struck a reconciliatory note, blaming the downing on a "chain of tragic, fatal circumstances." 

But the Russian military came out on Sunday, renewing the accusations against Israel.

Russian officials said Syria's outdated S-200 systems weren't sophisticated enough to identify the Russian plane as a friendly one.

Monday's statement from Russian Defence Minister Sergei Shoigu said Russia will send the newer S-300 missile defence systems to Syria within the next two weeks. 

Earlier in the war, Russia suspended a supply of S-300s, which Israel feared Syria could use against it.

Shoigu said Russia is now going to go ahead with the shipment because "the situation has changed, and it's not our fault." 

The supply of S-300s to Syria will "calm down some hotheads" whose actions "pose a threat to our troops," he said.

Russian Deputy Foreign Minister Mikhail Bogdanov told Russian news agencies that supplying S-300 to Syria is Russia's "own right" and expressed confidence that this would not hurt Russia's ties with Israel.

The Kremlin said Russia's decision was not targeted against anyone and only serves to protect Russian troops in Syria.

Spokesman Dmitry Peskov told reporters that recent findings by the Russian military showed an Israeli jet "deliberately" pushed the Russian Il-20 into the line of fire, enabling its downing.

Russia's stepped-up role in Syria enabled regime forces, which had been losing ground to the armed opposition, to gain the upper hand in the war and reclaim wide swaths of territory held by the rebels.

In recent months, the regime recaptured many areas that were controlled by rebels. 

And last week, Russia reached a deal with Turkey that averted a Russian-backed offensive against the northwestern province of Idlib, one of the last opposition and rebel-held areas in the country.

Idlib, controlled by a mix of militants, rebels, political opposition, Turkey-backed armed opposition and civilians overlooks the Syrian coast where Russia military and air bases are located, and have reportedly come under fire.

Source: AP