The death toll after yesterday's attack has risen to 25, according to the London-based Syrian Human Rights Observatory (SOHR), which calls it "one of the worst Israeli attacks" in Syria in years.
At least four civilians are said to be among the dead. More than 40 people are reported to have been injured.
Syrian state media, however, report a lower death toll of 16.
Denies presence
According to SOHR, the attacks were directed at a military research facility for chemical weapons in Masyaf and other locations where "Iran-backed militias and experts are stationed to develop weapons in Syria". Local media also reported attacks around the coastal city of Tartus.
The Iranian Foreign Ministry's spokesperson condemns what they call a "criminal" attack and denies that Iranian forces are present at the locations in question.
Syria's Foreign Ministry has also condemned the attacks and accused Israel of trying to provoke further escalation in the tense region.
Hundreds of attacks
Israel's military has not commented on the matter, but has carried out hundreds of attacks on targets in government-controlled parts of war-torn Syria in recent years. Israel has primarily targeted military positions and Iran-backed militia groups, including the Lebanese Hezbollah, which has supported Syria's President Bashar al-Assad during the 13-year civil war.
Since the Gaza War began, the alleged Israeli attacks have increased in intensity.
Israel has repeatedly claimed that it will not allow archenemy Iran to expand its presence in Syria.
