US President Donald Trump on Wednesday cancelled a visit to the tense Demilitarized Zone separating the two Koreas because bad weather ostensibly made it impossible for him to travel by helicopter to the border from Seoul.The president's helicopter convoy took off from the central Yongsan military base in Seoul, near the hotel where he is staying, but it had to return to the base a few minutes later due to poor weather conditions, the White House said, Efe reported.Washington had said publicly that it was ruling out a trip to the DMZ during Trump's two-day visit to South Korea, an Asia tour on which the president is addressing the military threat posed by North Korea.However, amid ironclad security, Trump decided to make a surprise visit to the border along with South Korean President Moon Jae-in as a symbol of the strong alliance between Washington and Seoul, Press Secretary Sarah Huckabee Sanders said."I think he's pretty frustrated," said Sanders, referring to Trump, who will travel to Beijing later on Wednesday."The fact they were planning to go still shows the strength of the alliance," she said.Thick fog blanketed the area and, although Trump's helicopter flew to within five minutes of the landing zone, authorities ultimately decided to cancel the trip.Moon's helicopter was diverted to another location also.On Tuesday, Trump scaled back his combative rhetoric toward Pyongyang, saying that Kim Jong-un's government should negotiate rather than threaten the US and its allies with its nuclear program.The president also did not rule out direct talks between the US and North Korea, saying at a joint news conference with Moon that "I really believe that it makes sense for North Korea to come to the table and to make a deal that's good for the people of North Korea and the people of the world.""I do see certain movement, yes, but let's see what happens," Trump said.North Korea has fired more than a dozen missiles on "test flights" this year, including over Japan, and it has been pursuing a nuclear weapons and ballistic missile program for some years.In response, Trump has threatened to respond to any hostile act by Pyongyang with "fire and fury" and there are presently three US aircraft carriers in the vicinity of the Korean Peninsula.