Sen. John McCain warned Tuesday the violent civil conflict in Syria will spread to neighboring countries unless the United States quickly intervenes.

“Those who want to leave this issue alone are not appreciative of how this is spreading — seeing deterioration in Iraq, al Qaeda … being restored in Iraq and Syria, the destabilization of Lebanon and Jordan. And the list goes on,” the Arizona Republican told CNN’s “The Situation Room.”

“This is turning into a regional conflict and we need to reverse it. Now is an opportunity to do so.”

McCain pressed President Obama for a sustained “retaliatory action,” including arming rebel forces opposed to Syrian President Bashar Assad’s regime.

“If it’s simply just going and doing some cruise missile strikes, then I think, again, it may be counter-productive,” McCain said. “In fact, it may give Bashar Assad a propaganda advantage by saying he was able to resist the United States’ attacks.”

But he stopped short of calling for U.S. troops to invade the Middle East country.

“It’s not requiring [U.S.] boots on the ground. It’s not requiring serious things except supplying people with weapons with which to defend themselves and taking out the air assets,” he said.

“To sit by and watch the region deteriorate into chaos is something that is not in the United States’ national security interests, not to mention our humanitarian view of [the] massacre of well over 100,000 people.”