Despite opposition from Israel and the United States, Russia has begun giving S-300 air-defense systems to the Syria, according to Russian Foreign Minister Sergey Lavrov.

“The deliveries started already,” Lavrov said at a press conference on Friday. “The measures we will take will be devoted to ensure 100 percent safety and security of our men in Syria, and we will do this.”

Russia said last week that it would deliver Syrian President Bashar Assad’s regime with advanced anti-aircraft missile systems in the aftermath of an Israeli airstrike earlier this month, which was mistakenly shot down by a Russian military plane, killing all 15 of its crew members.

The incident sparked tensions between Jerusalem and Moscow, causing Israeli military officials to meet with their Russian counterparts in the latter city.