U.S. President Donald Trump on Friday continued to downplay North Korea's three tests of short-range ballistic missiles over eight days as Pyongyang's Foreign Ministry appeared to open the door to the possibility of even more powerful tests in the near future.

Trump blasted out a series of tweets in which he said the recent spate of launches did not run counter to the vaguely worded, 1½-page joint statement he agreed to with North Korean leader Kim Jong Un in Singapore during their landmark first summit in June last year.

"Kim Jong Un and North Korea tested 3 short range missiles over the last number of days," Trump wrote. "These missiles tests are not a violation of our signed Singapore agreement, nor was there discussion of short range missiles when we shook hands."