President Donald Trump delivered a sharp warning to North Korea Wednesday, telling the rogue nation: "Do not underestimate us. And do not try us."

In a speech delivered hours after he aborted a visit to the heavily fortified Korean demilitarized zone due to bad weather, Trump said he had a message for North Korean leader Kim Jong Un.

"The weapons you are acquiring are not making you safer, they are putting your regime in grave danger," Trump told an audience of South Korean lawmakers, calling on all nations to join forces "to isolate the brutal regime of North Korea."

"The world cannot tolerate the menace of a rogue regime that threatens with nuclear devastation," he said.

Trump had hoped to underscore his message with an early morning visit to the DMZ, but his plans were thwarted by heavy fog that prevented his helicopter from landing at the heavily fortified border that has separated the North and South for the last 64 years.

The Marine One helicopter left Seoul at daybreak and flew most of the way to the DMZ, but was forced to turn back just five minutes out due to poor weather conditions. Reporters traveling in a separate helicopter as part of the president's envoy saw fog through the windows, and weather reports from near the heavily fortified border showed misting conditions and visibility below one mile. Pilots, officials said, could not see the other helicopters in the air.

White House press secretary Sarah Huckabee Sanders said the president was disappointed he couldn't make the trip. "I think he's pretty frustrated," she told reporters. "It was obviously something he wanted to do."

Before he left for Asia, a White House official had ruled out a DMZ visit for Trump, claiming the president didn't have time on his schedule and that DMZ visits have become a little cliché.

But Sanders said the visit had been planned well before Trump's departure for Asia. The trip was kept secret for security reasons, she said.

The aborted visit came hours before Trump addressed the South Korean National Assembly as he closed out his two-day visit to the nation and headed to his next stop, Beijing.