North Korean leader Kim Jong Un crossed over the border into South Korea on Friday, becoming the first North Korean leader to step foot on South Korean-controlled territory.

Kim and South Korean President Moon Jae-in shook hands while standing on both sides of the military demarcation line before Moon joined Kim on the northern side of the border.

The two leaders then crossed over to the South for the summit, where they are expected to discuss the denuclearization of the Korean peninsula.

The two leaders are also set to discuss a peace treaty to formally end the Korean War of the 1950s.

The summit comes as the U.S. and North Korea prepare for a potential meeting between Kim and President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE.

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Following the largely symbolic move at the border on Friday local time, the U.S. voiced optimism that progress could be made on Pyongyang giving up its nuclear weapons.

"On the occasion of Republic of Korea President Moon Jae-in’s historic meeting with North Korean leader Kim Jong Un, we wish the Korean people well. We are hopeful that talks will achieve progress toward a future of peace and prosperity for the entire Korean Peninsula," White House press secretary Sarah Huckabee Sanders said.

"The United States appreciates the close coordination with our ally, the Republic of Korea, and looks forward to continuing robust discussions in preparation for the planned meeting between President Donald J. Trump and Kim Jong Un in the coming weeks."

Relations between the U.S. and North Korea appear to have improved as the Trump administration pushes for the North to give up its nuclear ambitions.

The White House on Thursday released pictures of newly minted Secretary of State Mike Pompeo Michael (Mike) Richard PompeoOvernight Defense: Pentagon redirects pandemic funding to defense contractors | US planning for full Afghanistan withdrawal by May | Anti-Trump GOP group puts ads in military papers Overnight Defense: House Democrats unveil stopgap spending measure to GOP opposition | Bill includes .6B for new subs | Trump issues Iran sanctions after world shrugs at US action at UN Navalny calls on Russia to return clothes he was wearing when he fell ill MORE's secret meeting with Kim over the Easter weekend earlier this month.

Trump, who once frequently referred to Kim as "little rocket man," called him "honorable" earlier this week.

The inter-Korean summit this week follows a year of tension between Pyongyang and the international community.

North Korea conducted a slew of intercontinental ballistic missile tests last year despite strong condemnation and sanctions from the international community.