Shares linked to inter-Korean economic cooperation skyrocketed, Tuesday, as U.S. President Donald Trump said North Korean leader Kim Jong-un had responded to his proposal for talks, according to the Korea Exchange.

Good People soared 30 percent to close at 429 won ($0.31), hitting the daily price ceiling. Codes Combine and In the F also surged 30 percent and 29.81 percent, respectively, to close at 3,510 won and 2,395 won.

Good People and In the F are considered inter-Korean cooperation stocks due to their past operations in the Gaeseong Industrial Complex. Codes Combine is also included because its largest shareholder previously operated there.

Launched in 2004, the Gaeseong Industrial Complex was a jointly operated economic zone in North Korea, largely financed by South Korea to promote inter-Korean cooperation. In February 2016, the Park Geun-hye administration shut down the complex, citing concerns that funds generated there could be diverted to finance North Korea's weapons programs.

Seen as a barometer of inter-Korean relations, shares of South Korean companies with ties to the Gaeseong Industrial Complex tend to swing sharply in response to developments involving North Korea.

Shares of Ananti and Ilshin Stone also climbed 13.92 percent and 15.59 percent, respectively, to close at 4,500 won and 698 won. Ananti previously pursued golf course and resort projects in the Mount Geumgang tourism zone, while Ilshin Stone's largest shareholder, the Unification Church, has a history of doing business with North Korea.

The gains came as Trump fueled hopes for renewed dialogue with North Korea.

Trump posted a doctored image on Truth Social on Tuesday showing Kim holding a phone, with the caption, "Hey Donald, We cool ... Right?" The post appeared to suggest that the two leaders were close enough for Kim to address Trump by his first name.

Trump also told reporters at the White House that Kim had responded to his request for talks. Asked what stage the discussions had reached, Trump described them as "very positive." He did not specify when or how Kim had responded.

The remarks came a day after Trump ordered Defense Secretary Pete Hegseth to "substantially reduce" joint military drills with South Korea to avoid sending what he called "a signal that is totally inappropriate and hostile" to North Korea. The allies are holding joint military exercises from Monday through Aug. 27.