(CNN) North Korea has dropped its long-held demand that the United States withdraw forces from South Korea in exchange for denuclearization, South Korean President Moon Jae-in said Thursday.

The United States has about 28,000 troops stationed in South Korea, a presence that has long irked North Korean leader Kim Jong Un.

However, in the burgeoning spirit of openness and diplomacy, Moon said Kim is willing to give up US troops' removal as a precondition for discussions over denuclearizing the Korean Peninsula.

"North Korea has expressed willingness to give up its nuclear program without making (a) demand that the (US Forces Korea) forces withdraw from the Korean Peninsula," Moon said in a meeting with the press, adding that any proposed troop withdrawal would be a "condition that the US cannot accept."

The South Korean leader, due to meet Kim next week for a historic summit in the Demilitarized Zone, the border separating the two countries, said the North was concerned about its security.

Ahead of the talks, a hotline between the two capitals was reconnected Friday afternoon.

"A test call between working-level officials will be made (Friday)," South Korean presidential spokesman Kim Eui-kyeom said Thursday.

"One end of the phone line is the Blue House and the other end is North Korea's Cabinet Committee. It is not decided yet when the two heads of the state will make a call."

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"They only talk about ending the hostile policy against North Korea, and then guarantee of their security. With that clarification, the US and North Korea have agreed to sit down at the summit," he said.

Officials from the two Koreas will conduct rehearsals for the inter-Korean summit ahead of the meeting, Kim Eui-kyeom, spokesman for South Korea's Blue House, said on Thursday.

According to Kim, South Korea will have two rehearsals, one on April 24 in the afternoon and one on April 26. North Korean officials will conduct one rehearsal ahead of the summit on the 27th.

The concession comes as President Donald Trump insisted Wednesday he'd be willing to leave a highly anticipated summit meeting with Kim should it fall short of his expectations.

"If we don't think it's going to be successful, we won't have it," Trump said. "If the meeting when I'm there isn't fruitful, I will respectfully leave the meeting."

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Joint drills no longer an issue

In a similar vein, Kim signaled in March that he would not oppose joint US-South Korean military exercises, which had been postponed while South Korea hosted the Winter Olympics.

The annual war games have been a sore point for the North Korean leader, who sees them as a direct provocation to his country's security.

A South Korean delegation that traveled to Pyongyang reported back that Kim understands Seoul's position on holding military drills with the United States.

"Our stance on the joint military drills is that it is hard to postpone the exercises again or suspend them, and there is no justification for doing so. But Kim said that he understands the South's stance," a high-level official in South Korea's presidential office told CNN in March.

According to the official, Kim also said he expects the joint drills to be "readjusted" once the security situation on the Korean Peninsula stabilizes.

US military leaders have refused to put the drills on the table as a negotiating chip.

Rapid thaw in relations

Kim's diplomatic skills seem to have developed rapidly since Moon, a liberal who favors a more open policy toward the North, took office in May -- and particularly since the beginning of the year.

A conciliatory New Year's Day message from Kim swiftly saw the reconnection of a cross-border hotline, a development that led to the North's athletes and cultural ambassadors taking part in the South Korean-hosted Winter Games.

Since February, high-level talks between Seoul and Pyongyang have occurred, leading to an unlikely invitation from the North Korean leader to Trump for a face-to-face meeting and, indirectly, Kim's first foreign visit to neighbor and ally China.

Cultural exchanges have also warmed relations on either side of the 38th parallel, most recently with a performance by South Korean pop acts in the North Korean capital.

Following the groundbreaking concert, South Korean Culture Minister Do Jong-hwan told CNN that Kim seemed "sincere and genuine" about wanting to improve relations with Seoul.

The two Korean leaders prepare to meet next week in what is seen as paving the way for the US-North Korea summit.

This week it emerged that CIA Director Mike Pompeo, Trump's nominee for secretary of state, traveled to the North Korean capital for secret, preliminary talks ahead of the Trump-Kim meeting, which is set for late May or early June.