A US strike on a Syrian airbase ordered in retaliation for a suspected chemical weapons attack killed four soldiers on Friday and virtually destroyed its facilities, a monitoring group said.
"An air commodore was among the four soldiers killed," the Syrian Observatory for Human Rights said.
"The airbase was almost completely destroyed -- the runway, the fuel tanks and the air defences were all blown to pieces," the Britain-based monitoring group said.
"There were Sukhoi-22, Sukhoi-24 and MiG-23" fighter aircraft on the ground, Observatory chief Rami Abdel Rahman told AFP.
The officers' quarters at Shayrat, the government's second most important airbase, were also damaged,he added.
Only Latakia airbase in the heartland of President Bashar al-Assad's regime on the Mediterranean coast, where his ally Russia also maintains extensive facilities, is more extensive.
Washington said that Russian military officials in Syria were informed of the strike beforehand in order to avoid casualties that could prompt a broader crisis.