BEIJING -- U.S. Secretary of State Rex Tillerson on Saturday pushed for closer China-U.S. cooperation on dealing with North Korea’s nuclear program in his first face-to-face talks with top Chinese diplomats.

When Tillerson arrived in the country, he stepped into an arena where the U.S. is facing a barrage of challenges from trade to the South China Sea, but America’s biggest foreign policy problem - North Korea - topped the agenda, CBS News correspondent Adriana Diaz reports. Tillerson has to win over China to have any hope of combating the threat from the North.

Tillerson’s visit to Beijing followed his remarks in South Korea on Friday in which he warned that pre-emptive military action against North Korea might be necessary if the threat from its weapons program reaches a level “that we believe requires action.”

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China, the North’s biggest source of diplomatic support and economic assistance, hasn’t responded directly to his remarks, although Beijing has called repeatedly for all sides to take steps to reduce tensions.

Tillerson stressed the need for a “results oriented” relationship with China in comments following his meeting Saturday with Foreign Minister Wang Yi.

“We renewed our determination to work together to convince North Korea to choose a better path and a different future for its people,” Tillerson said.

He said Wang agreed on the need for a “course correction” with Pyongyang. Bringing North Korea “to a different place” is a matter to be approached with “a sense of urgency,” Tillerson said.

U.S. Secretary of State Rex Tillerson and Chinese Foreign Minister Wang Yi shake hands at the end of a joint press conference at the Diaoyutai State Guesthouse in Beijing, China, March 18, 2017. Reuters/Mark Schiefelbein

Wang restated Beijing’s calls for dialogue between the U.S. and North Korea and called Tillerson’s visit an important step toward a meeting between Chinese President Xi Jinping and his U.S. counterpart, President Trump, expected next month.

Tillerson met later with Yang Jiechi, Xi’s top foreign policy adviser. He is scheduled to meet with Xi on Sunday morning before returning to the U.S.

As North Korea’s most important source of diplomatic support and economic assistance, China has grown increasingly concerned about the possibility of conflict on the Korean Peninsula.

Wang warned last week that North Korea on one side, and the U.S. and South Korea on the other, were like “two accelerating trains” headed at each other, with neither side willing to give way.

He floated a proposal that North Korea could suspend its nuclear and missile activities in exchange for a halt in joint U.S.-South Korea military drills. That was swiftly shot down by the U.S. ambassador to the United Nations, Nikki Haley, who said Washington has to see “some sort of positive action” from North Korea before it can take leader Kim Jong Un seriously.

While China has agreed reluctantly to U.N. Security Council resolutions sanctioning North Korea, it is adamantly opposed to measures that might bring about a collapse of the North Korean regime and send waves of refugees into northeastern China while South Korean and American forces take up positions on its border.

That’s left Beijing with few options other than to call for renewed dialogue under the Beijing-sponsored six-nation format that broke down in 2009.

In a further sign of its frustration with Pyongyang, China last month banned imports of North Korean coal for the rest of the year, potentially depriving Kim’s regime of a key source of foreign currency.

On Friday, Tillerson signaled a tougher strategy toward North Korea that leaves open the possibility of pre-emptive military action.

“Let me be very clear: The policy of strategic patience has ended,” he said after visiting the heavily militarized border between the rival Koreas. “We are exploring a new range of diplomatic, security and economic measures. All options are on the table.”

Past U.S. administrations have considered military force because of North Korea’s development of nuclear weapons and ballistic missiles to deliver them, but rarely has that option been expressed so explicitly as by Tillerson.

North Korea has accelerated its weapons development, violating multiple Security Council resolutions without being deterred by sanctions. The North conducted two nuclear test explosions and 24 ballistic missile tests last year. Experts say it could have a nuclear-tipped missile capable of reaching the U.S. within a few years.

China has stridently opposed the deployment of a U.S. missile defense system to South Korea, saying its X-band radar can peer deep into China to monitor flights and rocket launches. The U.S. says it’s a system focused purely on North Korea and poses no threat to the security of other nations.

Tillerson’s visit to Beijing is the final stop on his three-nation swing through Northeast Asia, which began in Japan. State Department officials have described it as a “listening tour” as the administration seeks to coordinate with its Asian partners on a coherent North Korea policy.

Though it didn’t come up in his public remarks, Tillerson was expected to discuss with China its claim to virtually the entire South China Sea, including its building of islands atop coral reefs, complete with airstrips and military installations.

During his confirmation hearings in January, Tillerson compared China’s island-building and deployment of military assets to Russia’s 2014 annexation of Crimea, and suggested that China’s access to its newly built islands should be blocked.

While Mr. Trump pledged during his campaign to slap 45 percent tariffs on imports from China and label the country a currency manipulator, there has been little indication of his doing either. His pick for U.S. trade representative, Robert Lighthizer, has said he would use a “multifaceted approach” to cracking down on Chinese trade abuses.

Tillerson’s trip also highlights the Trump administration’s apparent lack of concern with human rights abuses in countries overseas, formerly a key element of U.S. policy toward China - and a major irritant in bilateral relations.

In a departure from past practice, Tillerson skipped the launch of an annual report on human rights last week that cited numerous abuses by China. He has also said the U.S. would not continue participating in the U.N. Human Rights Council unless it undergoes “considerable reform.”