The US and South Korea on Friday pledged continued, close coordination to maintain maximum pressure on North Korea over its nuclear programme and said the country can could enjoy a "brighter future" if it chooses the correct path.

US President Donald Trump spoke over phone with his South Korean counterpart Moon Jae-in over the upcoming engagement with the North Korean leader Kim Jong-un and the preparations related to it, the White House said.

Both leaders affirmed the importance of learning from the mistakes of the past, and pledged continued, close coordination to maintain maximum pressure on the North Korean regime, the White House said.

The two leaders agreed that concrete actions, not words, will be the key to achieving permanent denuclearisation of the Korean Peninsula, and Trump reiterated his intention to meet with North Korean leader Kim Jong Un by the end of May, it said.

Trump and Moon expressed cautious optimism over recent developments and emphasised that a brighter future is available for North Korea, if it chooses the correct path, the readout of the call said.