North Korean leader Kim Jong Un met with Chinese President Xi Jinping in Beijing during a visit this week, according to Chinese and North Korean state media. The trip marks the first known time Kim has left North Korea since taking power in 2011 and the first face-to-face meeting between Xi and Kim.

The reports come a day after rumors of Kim's arrival via a mysterious train and ahead of potential talks between the U.S. and the North over North Korea's nuclear and missile programs. China is North Korea's closest ally.

Kim was in the country from Sunday to Wednesday. China's state-run Xinhua news agency aired footage of the two leaders touring Chinese government buildings, and quoted Kim as saying, "We're determined to turn South-North relationship into a cooperative one and holding a meeting between two leaders. We're willing to hold dialogues with the U.S. and hold meetings between two leaders. If the South and the U.S. reacts with kindness, denuclearization could be solved."

Press secretary Sarah Huckabee Sanders said Tuesday the White House had been contacted by the Chinese government about the meeting. The briefing included a "personal message from President Xi to President Trump, which has been conveyed to President Trump," Sanders said.

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"The United States remains in close contact with our allies South Korea and Japan," Sanders said. "We see this development as further evidence that our campaign of maximum pressure is creating the appropriate atmosphere for dialogue with North Korea."

Xi held talks with Kim at the Great Hall of the People in Beijing and he and his wife Peng Liyuan hosted a banquet for Kim and his wife Ri Sol Ju, Xinhua said. They also watched an art performance together, the news agency said.

Analysts said Kim would have felt a need to consult with his country's traditional ally ahead of his planned meetings with South Korean President Moon Jae-in and President Trump.

The North's diplomatic outreach came after an unusually provocative year when it conducted its most powerful nuclear test to date and three ICBMs tests designed to target the U.S. mainland. The developments were interpreted as the North being desperate to break out of isolation and improve its economy after being squeezed by heavy sanctions.

Kim was quoted in Xinhua news agency as saying he is open to a "dialogue" and a "summit" with the U.S., although he did not mention Mr. Trump by name, said "Face the Nation" moderator and CBS News' senior foreign affairs correspondent Margaret Brennan reports.

China remains North Korea's only major ally and chief provider of energy, aid and trade that keep the country's broken economy afloat.

Kim's father, late North Korean leader Kim Jong Il, visited China several times during his rule, lastly in May 2011, months before his death.

Past visits by Kim Jong Il to China were surrounded in secrecy, with Beijing only confirming his presence after he had crossed the border by train back into North Korea.

Chinese media reported a heavy police presence Monday at a Beijing guest house where foreign leaders often stay. Roads were closed and streets cordoned off, only fueling the idea that Kim had slipped into the Chinese capital. Tourists were cleared off Tiananmen Square, which normally only happens for important meetings, CBS News' Ben Tracy reported.