A massive explosion at a Latakia air base in northwestern Syria was the result of an Israeli attack, according to White House officials. The site contained shipments of Russian anti-aircraft missiles.

The first reports on the strike came out of al-Arabiya, and they claimed a second, still-unconfirmed strike in Damascus as well. Casualties are unclear, but Syria’s state media insisted there were no injuries.

Lebanese news outlets reported Israeli warplanes violating their airspace earlier Wednesday afternoon, and they left the airspace north of Tripoli, heading out to sea, in the early evening. After that, the warplanes attacked Latakia from the sea.

The reports claim that the Latakia base “possibly contained” Russian SA-8 missiles, and that those missiles were potentially headed to Hezbollah, though neither of these assertions has been proven. Israel has repeatedly attacked Syria over the past year.