The was a "one-time strike," the head of the Pentagon said. The full operation was completed in less than 60 minutes.
Three main chemical weapons-related sites were targeted, as well as one command center, according to the Joint Chiefs of Staff (JCS).
Continued air strikes will not take place, unless Assad uses chemical weapons again, Mattis told reporters.
"With regard to the Russian concern, we specifically identified these targets to mitigate the risk of Russian forces being involved," the chairman of the JCS said.
The deconfliction line with Russia was "active" this week, Dunford noted. US Central Command followed normal protocols when communicating across the deconfliction channel with Russia for clearing the airspace, JCS said.
"This wave of strikes is over," Dunford emphasized. When asked how many missiles were intercepted, Dunford said simply, "I don't know," before stating that US Central Command would have more details over the weekend. The Syrian Arab News Agency reported that air defense systems intercepted 20 missiles.
The United States does not know about any Russian defense systems engaged in airstrikes on Syria, Joint Chiefs of Staff Chairman Gen. Joseph Dunford told reports.
"I am not aware of any Russian activity," Dunford said.