MOSCOW — President Vladimir V. Putin said Monday that Russia would supply the Syrian military with a sophisticated air defense system, a move that reflects Russia’s increasing tensions with Israel and that could heighten the risks of the air war over Syria.

Israel, which has long opposed the weapons transfer, has carried out more than 200 strikes on Iranian-affiliated targets in Syria in the past two years as Russia, Syria’s main patron, has mostly looked the other way.

But relations between Russia and Israel have frayed since a Russian military plane was shot down over Syria a week ago, killing 15 Russian service members. The plane was accidentally shot down by Syria in response to an Israeli airstrike.

After Russia initially blamed Israel, Mr. Putin appeared last week to accept the loss as an accident.

But on Monday, Russia’s defense minister said the decision to send the sophisticated S-300 missiles to Syria was made in response to Israel’s disregard for the safety of Russian military personnel. Israeli pilots, he said, had intentionally maneuvered near the Russian plane to shield themselves from attack by Syria, putting the Russian crew at risk.