The Syrian army said that Israeli air strikes targeted a military post near Masyaf in the Hama province on Thursday morning, killing two of its troops.
“Aircraft of the Israeli enemy at 2.42am launched a number of missiles from Lebanese airspace and targeted one of our military positions near Masyaf, resulting in the martyrdom of two of our troops and in material damage,” the Syrian army general command said in a statement.
“This aggression is a desperate attempt to raise the collapsed morale of the terrorist ISIL group after the victories of the Syrian army against terrorism on more than one front. It also affirms Israel’s direct support of ISIL and other terrorist organisations."
The British-based Syrian Observatory for Human Rights said that part of the complex that was struck was a military research facility, Scientific Studies and Research Centre, which the US and former Israeli officials have accused of helping develop sarin gas.
According to Reuters, an Israeli army spokeswoman declined to discuss reports of a strike in Syria, saying that the military did not comment on operational matters.
The Lebanese military could not immediately verify that the strike was launched from Lebanese airspace, but Israeli aircraft routinely fly over Lebanon in violation of UN Security Council Resolution 1701.
Israel has in the past admitted to attacking arms shipment allegedly bound for Lebanon’s Hizbollah group, which is fighting alongside Syrian president Bashar Al Assad’s forces. Israel rarely takes public credit for such strikes, though it is believed to have carried out nearly 20 of them since 2013.
Yaakov Amidror, Israel’s former national security adviser, told The Associated Press that the strike targeted a weapons development and manufacturing site that was producing arms for Hizbollah.
Israeli strikes inside Syria predate the civil war as far back as the Six-Day War in 1967, when Israel preemptively struck airfields in the country. In the 1980s, targets were often Palestinian militants.
More recently, in 2007, Israeli planes are believed to have destroyed a nuclear reactor near the city of Deir Ezzor. Israeli planes are also believed to have struck a military research facility near Damascus in 2013.
The strike comes a day after the UN said the Syrian government was responsible for a chemical weapons attack in April against the northern city of Khan Sheikhoun that killed more than 80 people.
That attack prompted the US to launch air and missile strikes against the Syrian government.
Syria has claimed that it destroyed all of its chemical weapons as part of an agreement reached in 2013 after a chemical weapons attack killed as many as 1,400 people in the suburbs of Damascus. The UN did not assign blame in that attack, though it is widely thought it was carried out by the Syrian government.
The Organisation for the Prevention of Chemical Weapons, which oversaw the destruction of the weapons, has cast doubt on the Syrian government’s assertions that all the weapons were handed over.
The Khan Sheikhoun attack was just one of 33 chemical weapons attacks that it has documented. All but six have been attributed to Assad forces.
Israel’s repeated strikes, as well as the US’s in April, have called into question the efficacy of advanced Russian S300 and S400 air defence systems that were first shipped to Syria in 2013. Israel is believed to have carried out a pair of strikes to destroy some of those systems in 2014.
Retired Israeli Gen Amos Yadlin tweeted that the strike was a demonstration “Israel intends to enforce its redlines despite the fact that the great powers are ignoring them”.
“Now it’s important to keep the escalation in check and to prepare for a Syrian-Iranian-Hizbollah response and even opposition from Russia,” tweeted Mr Yadlin, who currently serves at the executive director of Tel Aviv University’s Institute for National Security Studies.
Iran and Russia both support the government and military of the Syrian president, along with Hizbollah.
“It's extraordinary in terms of the target,” said Andrew Tabler, a fellow at the Washington Institute for Near East Policy. “They were after one of the Syrian Scientific Studies and Research Centre bases — not a simple weapons convoy.”