President Donald Trump and Chinese President Xi Jinping. AP Photo/Alex Brandon When US President Donald Trump and Chinese President Xi Jinping were enjoying chocolate cake at the end of their first dinner together on Thursday, US Navy ships were pounding a Syrian airfield with a salvo of 59 cruise missiles.

After a phone call on Tuesday night, the two signaled an agreement to work together to denuclearize North Korea, and China reportedly sent 150,000 troops to North Korea's border.

The Trump administration has long tried to establish its willingness to use military force against Kim Jong Un's regime.

"China insists on realizing the denuclearization of the peninsula ... and is willing to maintain communication and coordination with the American side over the issue on the peninsula," Xi was quoted as saying by the state broadcaster CCTV and other official media outlets after the call.

"Had a very good call last night with the President of China concerning the menace of North Korea," Trump tweeted on Wednesday morning. Trump last month said China could end the North Korean crisis easily if it wanted to, but it had "done little to help."

China has resisted taking hard action against North Korea since it has a vested interest in preserving the state, which acts as a physical and cultural buffer between China and the Western-oriented, democratic South Korea.

But now, as the US Navy's USS Carl Vinson carrier-strike group looms just off the Korean peninsula, multilateral talks hold more promise than ever.

Xi's response after his meeting with Trump signals he may be willing to go further in reeling in the rogue North Korean leader. Trump reportedly stressed the issue and suggested the US would unilaterally take care of the Kim regime if necessary.

The aircraft carrier USS Carl Vinson (CVN 70) in the South China Sea. Thomson Reuters

But experts have told Business Insider that US military action against North Korea was never likely or plausible — North Korea just has too many guns aimed at South Korea.

"The Chinese are smart enough to think about the various military options, so they probably have concluded that there's a very low likelihood" the US would strike North Korea, said Bonnie Glaser, director of the China Power Project at the Center for Strategic and International Studies.

"I think it's almost a universal that with military strikes the downsides are just so great that it's hard to see them taking place," said Joel Wit, the founder of 38 North, a website that brings together experts on North Korea.

But the Chinese seem to have been spooked by the deployment of a high-tech US missile-defense battery to South Korea, reportedly because of its advanced radar capabilities.

China is responsible for 85% of North Korea's external trade and a similar percentage of its energy imports.

An entrance in Sinuiju, North Korea, to the "Korea China friendship bridge," which connects the two socialist states over the Yalu River. AP

While China has signed onto every UN Security Council resolution against North Korea since 2006, "it has, of course, watered down most if not all of those Security Council resolutions because it has not wanted to agree to sanctions that might create instability in North Korea," Glaser said. "And if it won't cause instability, it's probably not likely to be tough enough to cause Kim Jong Un to rethink his strategy and priorities."

So while China may have been swayed to act against its own interests by the Trump administration's military posturing, another more credible threat could have moved the needle.

"I think that [the Chinese] are quite worried about what Trump might do in the area of trade and economics — that's really credible," Glaser said.