President Trump said on Tuesday said "the world is watching" North Korea after the regime promised not to use nuclear or conventional weapons against Seoul and expressed a willingness to hold talks with the United States on denuclearization.

President Trump tweeted hours after South Korea’s presidential national security director, Chung Eui-yong, released a statement detailing his rare two-day visit to North Korea. He praised the "possible progress" but remained cautious.

Kim Jong Un and South Korean National Security Director Chung Eui-yong in Pyongyang. (KCNA via KNS)

“Possible progress being made in talks with North Korea. For the first time in many years, a serious effort is being made by all parties concerned. The World is watching and waiting! May be false hope, but the U.S. is ready to go hard in either direction!” Trump tweeted.

An error occurred while retrieving the Tweet. It might have been deleted.

The Hermit Kingdom added that it’s willing to give up its nuclear weapons if military threats against North Korea subsides, Chung said hours after leaving Pyongyang.

"The North side clearly affirmed its commitment to the denuclearization of the Korean Peninsula and said it would have no reason to possess nuclear weapons should the safety of its regime be guaranteed and military threats against North Korea removed," Chung said in a statement, according to Yonhap News Agency.

WHAT KIM JONG UN’S SISTER REALLY MEANS WHEN CALLING FOR NORTH AND SOUTH ‘UNIFICATION’

Chung, who led a 10-member South Korean delegation to Pyongyang for the two-day visit, said the North is ready to have “heart-to-heart” talks with the U.S. about the regime’s potential denuclearization and normalization between the countries.

"[North Korea] made it clear that while dialogue is continuing, it will not attempt any strategic provocations, such as nuclear and ballistic missile tests."
— Chung Eui-yong, national security director of South Korea

“It made it clear that while dialogue is continuing, it will not attempt any strategic provocations, such as nuclear and ballistic missile tests,” the statement continued.

North and South Korea agreed to hold summit talks in April at the border. The leaders will establish a “hotline” communication channel to lower military tensions, Chung added.

Secretary of State Rex Tillerson on Tuesday called for countries to further isolate North Korea despite the Hermit Kingdom's offer to discuss denuclearization.

“North Korea threatens the entire global community through its unlawful nuclear and ballistic missile programs and proliferation activities, including its arms exports to Africa. It doesn’t just involve our allies in Europe or Asia. It doesn’t just include countries with longstanding ties to [North Korea] like China and Russia. This is and must be a global effort," Tillerson said in a speech at George Mason University.

Kim Jong Un and Chung Eui-yong talked during a two-day visit. (KCNA via KNS)

The comments mark a major change in tone after months of bombastic threats by the rogue regime to keep developing its nuclear and missile program.

Chung-in Moon, the foreign policy adviser to Moon, told Fox News: “I think Kim Jong Un’s proposal is real and authentic. It is now up to President Trump as to how he responds. The devil is in the details.”

Last month’s Pyeongchang Olympics sparked the first talks between the two Koreas that followed a flurry of cooperative steps taken to ease tensions during the Winter Games.

North Korea sent a delegation of athletes, cheerleaders, art troupe members and officials to Pyeongchang for the Olympics. Kim’s sister, Kim Yo Jong attended the opening ceremony and met with South Korean President Moon Jae-in over a three-day visit. At one point, she even wrote of her “wishes” for closer ties in a guest book at South Korea’s presidential office.

South Korean President Moon Jae-in and Kim's sister Kim Yo Jong met during the Winter Olympics. (Reuters)

"I expect Pyongyang and Seoul to get closer in the hearts of our [Korean] people and the future of unification and prosperity will be advanced," Kim wrote in Korean in the guest book, according to Yonhap News Agency.

KIM JONG UN'S HARD CURRENCY EXPECTED TO RUN DRY BY OCTOBER, SOUTH KOREAN LAWMAKER SAYS

But the “future of unification” phrase means something far more sinister for the Kim family and his regime. North Korea has touted unification as a “final victory” to the Korean War that ended in an armistice in 1953. In Pyongyang’s view, "unification" means Kim’s brutal dictatorship would overcome the South’s government.

There have been two summits, one in 2000 and another in 2007, held between Kim's late father, Kim Jong Il, and two liberal South Korean presidents. They resulted in a series of cooperative projects between the Koreas that were scuttled during subsequent conservative administrations in South Korea.

Kim’s apparent olive branch to South Korea and the U.S. comes after months of mounting sanctions against the volatile regime. Kang Seok-ho, of the Liberty Korea Party, previously said the despot is scrambling to keep his regime afloat because the international sanctions was crippling its economy.

"I received an analysis that, if international sanctions against the North continue like this, all of North Korea's foreign currency earnings and overseas assets will be frozen, and its dollar [reserves] will dry up around October," Kang said.

Tillerson also said in mid-January there was “a lot of evidence that these sanctions are starting to hurt” North Korea.

Fox News' Greg Palkot and The Associated Press contributed to this report.