At least 42 soldiers were killed in Sunday's alleged Israeli strike in Syria, The Syrian Observatory for Human Rights, an opposition group, told AFP on Monday.

"At least 42 soldiers were killed in the strikes, and another 100 who would usually be at the targeted sites remain unaccounted for," Observatory director Rami Abdel Rahman said.

Earlier Monday, a high-ranking Syrian military source was quoted by the New York Times as saying that dozens of elite Republican Guard troops stationed by Syrian President Bashar Assad's palace in Damascus were killed in the strike.

The paper also quoted a doctor at the Syrian military’s Tishreen Hospital as saying there were at least 100 dead soldiers and many dozens more wounded.

Israel has not commented on two airstrikes early Sunday morning and early Friday, that allegedly targeted Iranian weapons destined for the Lebanese militant group Hezbollah.

Syrian President Assad on Monday threatened retaliation without warning to any further attack on his country, Kuwait daily Alrai reported.

Assad reportedly notified Washington via Moscow that orders had been given to allow deployed ground-to-ground and ground-to-air missile batteries to be used against Israel without advance notice in the event of another attack.

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