The Defense Department said Friday night that U.S., British and French forces struck three Syrian facilities that officials believe play a key role in Syria's ability to research, produce and store chemical weapons.

Defense Secretary Jim Mattis called it a "heavy strike" that was broader than the attack President Trump ordered one year ago that targeted an airfield. Friday night's strike aimed at the "long-term degradation" of Syria's chemical weapons capabilities.

“We used a little over double the number of weapons this year than we used last year," Mattis told reporters gathered for a late evening briefing at the Pentagon. "Right now this is a one-time shot."

The allied strike, with included manned U.S. aircraft, last about an hour and prompted the Syrian regime to retaliate by shooting surface-to-air missiles, said Gen. Joseph Dunford, the chairman of the Joint Chiefs of Staff.

Syrian state TV claimed the regime had shot down 13 U.S. Tomahawk cruise missiles. But Dunford said the U.S. was still reviewing the results.

“The only reaction that I’m aware of at this time is Syrian surface-to-air missiles … I’m not aware of any Russia activity and I’m not aware of the full scope of the Syrian regime response at this time," Dunford said.

The Pentagon was expected to give another detailed brief on the strike on Saturday morning.

Dunford confirmed that the U.S. used a deconfliction communication line to warn the Russians to remain out of the airspace around the target sites. But he said the U.S. did not share any targets with the Russians, and Moscow might not have known the warnings were connected to the chemical weapons strikes.

The deconfliction line is used regularly in Syria where the U.S. has been fighting the Islamic State and must work with the Russians to avoid any accidents or clashes.

However, Mattis said the U.S. and its allies specifically chose targets to avoid hitting the Russians, which he had said this week was his top concern about the operation.

Mattis said it's in the "vital national interest" to eliminate Syria's capacity to carry out attacks like the apparent chlorine gas attack on civilians from last Saturday that led to shock and anger around the world.

"Clearly, the Syrian regime did not get the message last year," he said. "This time our allies and we have struck harder. Together we have sent a clear message to Assad and his murderous lieutenants that they should not perpetrate another chemical weapons attack for which they will be held accountable."

Dunford said the allied mission was to destroy key targets that, once destroyed, should severely hurt Syria's ability to carry out further attacks.

"They will lose years of research and development data," he said.

Specifically, Dunford said the first target was a facility that served as a scientific research center, military facility and R&D center that focused on chemical and biological warfare. The second target was a chemical storage facility that the U.S. believes was a primary storage location for sarin gas.

The third target, he said, was a chemical weapons and command post facility.