John Bacon

USA TODAY

The United States and South Korea on Wednesday rejected China's proposal that the two nations suspend their expansive joint military exercise in return for North Korea suspending nuclear and ballistic missile development.

U.S. Ambassador to the United Nations Nikki Haley said North Korean leader Kim Jong Un's military programs defy international law and should not be negotiated. She said the annual joint military exercise, which involves thousands of U.S. servicemembers and hundreds of thousands of South Korean troops, have taken place for decades and are solely for defense.

"I appreciate my counterparts wanting to talk about talks and negotiations, but we are not dealing with a rational person," Haley said at a news conference in New York with the ambassadors from South Korea and Japan.

Haley said Kim must take "positive action" before he can be taken seriously at the negotiating table. She urged U.N. members to tighten sanctions and would not rule out any U.S. options, including military strikes.

Chinese Foreign Minister Wang Yi floated the "double suspension" plan earlier Wednesday after two days of increased tension on the Korean Peninsula. Wang, speaking in Beijing, said his plan could defuse a looming crisis, denuclearize North Korea and establish a foundation for further negotiations, the Chinese state-run news agency Xinhua reported.

Wang compared the political clashes pitting South Korea and the United States against North Korea to trains accelerating toward one another on the same track.

"Are the two sides really ready for a head-on collision?" Wang said. "The priority is to flash the red light and apply the brakes."

Wang said China is committed to a stable and peaceful Korean Peninsula, and that his country could be the "railway switchman" to get talks going.

U.S. moves missile defense to South Korea

Cho Tae-yul, South Korea's U.N. ambassador, echoed Haley's comments, saying dialogue won't work and tighter sanctions are needed.

"Linking these (military) exercises to anything else, an illegal nuclear provocation by North Korea is inappropriate and unacceptable," he said.

Wang will get to make his case personally to Secretary of State Rex Tillerson next week, when Tillerson makes his first official visits to China, South Korea and Japan. The former ExxonMobil chief executive will have plenty to discuss. On Monday, North Korea test-launched four ballistic missiles into the ocean near Japan, apparently in response to the annual military exercise now underway.

North Korea's state-run Korean Central News Agency said leader Kim Jong Un supervised the launches and that the goal was to prove North Korea's artillery units were capable of striking "U.S. imperialist aggressor forces in Japan."

President Trump discussed the launches with Japanese Prime Minister Shinzo Abe and South Korea's Acting President Hwang Kyo-Ahn late Monday. Abe later told reporters that North Korea's "threat has entered a new phase."

On Tuesday, U.S. Pacific Command announced that missile launchers and other military hardware needed to set up an anti-missile defense system were being moved into South Korea. The deployment of the Terminal High-Altitude Area Defense system was intended to intercept and destroy short- and medium-range ballistic missiles, military officials said.

That raised the ire of China, with Foreign Ministry spokesman Geng Shuang warning the U.S. and South Korea that there would be "consequences."

Contributing: Kim Hjelmgaard