President Trump expressed optimism Wednesday that the U.S. could find a way to address escalating tensions with North Korea, shortly after signaling he may reconsider relying on China to rein in Pyongyang.

"We're going to do very well," Trump told reporters at the White House on Wednesday before leaving for a four-day trip to Europe for the G-20 summit. North Korean aggression is expected to be a major topic of conversation.

Earlier Wednesday, Trump took to Twitter to highlight the recent growth in trade between China and North Korea. Trump has asked Chinese President Xi Jinping to caution Pyongyang against developing its nuclear capabilities.

"So much for China working with us - but we had to give it a try!" Trump tweeted on Wednesday.

North Korea claimed it successfully tested an intercontinental ballistic missile on Tuesday for the first time, marking a significant turning point for relations with the hermit kingdom. A functional ICBM could eventually allow North Korea to launch a nuclear strike as far as the U.S. homeland, a feat that is presently considered impossible for Pyongyang.

The White House has not indicated how Trump plans to handle the ICBM test. American and South Korean forces conducted a joint military exercise near the Korean Peninsula on Tuesday in response to the test.