A senior Israeli officer said Wednesday it was difficult to believe that President Bashar Assad did not know about the chemical attack on Syrian civilians earlier this month.

According to the officer, Israeli intelligence shows that the attack on the town of Khan Sheikhoun involved sarin gas and was carried out by senior officers in the Syrian army.

“It’s hard to believe that he didn’t know about it,” the officer said, adding that the use of these weapons pointed to “difficulties on Assad’s part. Using sarin shows that he’s deeply frustrated, and even though he has used chemical weapons in the past, this use created a change.”

The officer argued that the American missile attack on a Syrian air force base in response was not a strategic turnaround in the six-year Syrian war that has caused more than half a million deaths.

“The American attack is not a strategic turnabout but a combat development,” he said. The Israel Defense Forces was warned about the strike two hours in advance.

According to the officer, the IDF had no information on whether Russia knew about or approved the chemical attack. When asked whether Israel should respond to the use of chemical weapons, he said: “The State of Israel has no reason to jump into where the big powers are operating.”

Despite the Assad regime’s strengthening in western Syria, the regime doesn’t have the ability to decisively end the fighting, the officer said.

“I have a lot of difficulty envisioning the Syrian state returning,” he said. “I see no way [for Assad] to take control of Syria, even with all the Russian planes or 8,000 Hezbollah men.”

Over the past year Iran has lost its hegemony in Syria, the officer added. “Today there is Russian hegemony in the western parts of Syria,” he said.

Despite the firing of SA-5 missiles at Israeli fighter jets over Syria last month, the IDF says it will continue to foil Hezbollah’s efforts to obtain advanced weapons.

“From our perspective, the rules and principles remain the same,” the officer said. “We will continue to realize our interests, even in the near term.”