President Trump said Tuesday that efforts to get China's help pressuring North Korea have “not worked out” -- in the wake of imprisoned American college student Otto Warmbier's death.

Trump had reached out to Chinese President Xi Jinping early in his administration for help curbing Pyongyang's belligerent behavior. And while White House Press Secretary Sean Spicer moments earlier touted those efforts, Trump appeared to throw in the towel on Twitter Tuesday afternoon.

“While I greatly appreciate the efforts of President Xi & China to help with North Korea, it has not worked out. At least I know China tried!” Trump tweeted Tuesday afternoon.

Warmbier died days after North Korea released him. Trump on Tuesday called his treatment a "disgrace."

The U.S. response is unclear. Minutes before the president tweeted, Spicer told reporters that the administration had a “positive movement with China over the last five months” in an effort to “change the behavior” of Kim Jong Un’s regime.

“We have been very forceful in our political and economic pressure and we will continue to apply that,” Spicer said. “We will continue to build on our relationship and the dialogue we’ve had with China.”