U.S. President Donald Trump said Friday that his relationship with North Korean leader Kim Jong-un remains good despite reports of reassembling activity at a key North Korean missile site.

But he said he would be "very disappointed" if North Korea resumed the testing of nuclear weapons and ballistic missiles.

Speaking to reporters at the White House, Trump said that "time will tell,” but he believes his relationship with the North Korean leader "remains good." 

He said he would be surprised in a negative way if Kim did anything that was not per their mutual understanding, adding that he will see what happens.

His emphasis on good relations with Kim Jong-un appears to reflect his intent to continue a dialogue momentum.

But his comments about closely monitoring North Korea's movements are viewed as sending a warning against Pyongyang possibly resuming missile testing after rebuilding the Dongchang-ri test site. 

Trump and Kim's recent second summit in Hanoi, Vietnam ended without an agreement.