President and Chinese President may say little publicly about North Korea after they talk this week, but China has the leverage to quietly exert plenty of pressure on Pyongyang if it chooses, experts say.

North Korea sent a reminder about its weapons program when it fired a ballistic missile this week into waters off its east coast, just ahead of the first talks between the two presidents at Trump's private club, Mar-a-Lago, on Thursday and Friday. Trump may point to this latest incident as a way to get Xi on board to deal more seriously with 's nuclear ambitions.

"There's so much at stake, the Trump administration is going to work on a way forward. They're expecting much more from China. How Beijing responds to this call for action will be a clear signal to Trump on how serious they are about the U.S.-China tie," said Meredith Sumpter, director Eurasia Group.

"Ninety percent of North Korea's trade is with China, and the Trump administration sees that as clear leverage that China can use," said Sumpter.

China has tread softly with North Korea, in part for fear that making it unstable could result in a massive refugee flow across the Yalu River separating the two countries, destabilizing its own provinces and creating a domestic crisis.

"There is no love lost between Beijing and Pyongyang. Xi is in a tough space," said Sumpter. "He also has more experience with North Korea. Geographically speaking, his country is more at risk. By nature, Xi is going to be more cautious."

The U.S. has been toughening its talk on North Korea, with administration officials saying "the clock has run out" and "all options are on the table." Trump himself said in an interview last weekend that the U.S. will take unilateral action to end North Korea's nuclear threat unless China raises the pressure on Pyongyang.

"China has great influence over North Korea. And China will either decide to help us with North Korea, or they won't," Trump told the Financial Times. "If they do, that will be very good for China, and if they don't, it won't be good for anyone."