U.S. President Donald Trump will leave early Monday local time for his second summit with North Korean leader Kim Jong-un set for Wednesday and Thursday in Hanoi. 

Trump tweeted on Sunday that he believes North Korea could become a "great economic power" without nuclear weapons and that he and Kim expect a continuation of the progress made at their first summit in Singapore. 

The American president added "Chairman Kim realizes, perhaps better than anyone else, that without nuclear weapons, his country could fast become one of the great economic powers anywhere in the world."

According to Trump, Chinese President Xi Jinping has been "very helpful" in supporting his meeting with the North Korean leader.

Trump tweeted that the last thing China wants are large scale nuclear weapons next door, adding sanctions placed on the North Korean border by China and Russia have been very helpful.