BEIJING — China's foreign minister said Wednesday that North Korea could suspend its nuclear and missile activities in exchange for a halt in joint U.S.-South Korea military drills, in an unusually public proposal that analysts said showed Beijing's growing alarm over the tensions.

The U.S. and South Korea resisted the idea. Ambassador to the United Nations, Nikki Haley, said the U.S. has to see "some sort of positive action" from North Korea before it can take Kim Jong Un seriously. South Korea's ambassador called linking the annual drills to the North's provocations "unacceptable."

The ambassadors spoke after the Security Council condemned North Korea's latest volley of ballistic missile launches Monday that landed into ocean off Japan.

In Beijing, Chinese Foreign Minister Wang Yi said frictions between the North and Washington and Seoul were like "two accelerating trains" headed at each other, with neither side willing to give way.

"The question is: Are the two sides really ready for a head-on collision?" Wang told reporters. "Our priority now is to flash the red light and apply the brakes on both trains."

Wang said China has proposed that as a first step to defusing the looming crisis, the North might halt its nuclear program development and missile testing if the U.S. and South Korea suspended their military drills.

"This suspension-for-suspension can help us break out of the security dilemma and bring the parties back to the negotiating table," Wang said, describing the approach as trying to address all parties' concerns in a "synchronized and reciprocal" manner.

North Korea first floated the proposal in 2015, but it was swiftly dismissed by Washington and Seoul, who say the two issues are unrelated. Their view is that North Korea's nuclear and missile program is in violation of U.N. resolutions whereas the joint U.S.-South Korea drills are a long-standing practice.

Chinese scholars said Beijing has privately discussed this proposal with the countries involved but Wang's move to make it public could be a sign that China plans to take a more aggressive approach to the issue to prevent it from spinning out of control.

"China is becoming an utterly important victim of the turbulent situation on the Korean Peninsula, therefore it has unprecedentedly expressed its views in public," said Guo Rui, international relations expert at Jilin University.

China has been stepping up pressure on North Korea, its once-close Communist ally, to give up its nuclear and ballistic missile programs. Last month, Beijing suspended all coal imports from North Korea for the rest of the year, a move that deprives the North of an important source of foreign currency. Beijing wants the U.S. in return to restart long-stalled negotiations with North Korea.

Wang's move to publicize Beijing's proposal could also be directed at Washington ahead of Secretary of State Rex Tillerson's visit to China later this month.

At the U.N., Haley described North Korean leader Kim as irrational and seeking attention through provocative behavior.

Asked about China's proposal, Haley said: "We have to see some sort of positive action taken by North Korea before we can ever take them (North Korea) seriously."

South Korean Ambassador Cho Tae-yul said the military drills are defensive in nature, and said linking them to North Korea's nuclear and missile provocations is "inappropriate and unacceptable."

"This is not a time for us to talk about freezing or dialogue with North Korea," Cho said. "All kinds of options have been exhausted so far, so the only available means to change the North Korean behavior fundamentally is to continue to keep up the pressure and sanctions."

Wang likely renewed the dual suspension proposal in the hopes that President Donald Trump might see it as an alternative approach, said John Delury, a North Korea expert at Yonsei University's Graduate School of International Studies in Seoul.

"Wang Yi is putting it out there for Trump, saying 'here's an off-ramp to the current tensions,'" Delury said in a telephone interview from Seoul.

With tensions rising again, attitudes among officials and North Korea watchers are now diverging over how to approach the North, Delury said. While some want greater engagement, others are calling for stronger measures, possibly including military action, he said.

Trump, meanwhile, has yet to articulate a clear policy toward the North, other than to tweet that he wouldn't let it obtain nuclear weapons to attack America.

"The proposal is the same, but the context is different," Delury said.

Wang, who answered a range of questions at a briefing on the sidelines of China's annual national legislative sessions, also urged South Korea to suspend deployment of a U.S. anti-missile system, saying Seoul had made a "wrong choice."

Washington and Seoul say the system is defensive and not meant to be a threat to Beijing — a point reiterated by Haley on Wednesday. China is opposed to the system, saying it would allow U.S. radar to peer deep into its territory and monitor its flights and missile launches.

"We urge some forces in South Korea not to keep insisting on taking this path, otherwise the result can only be damage to others and harm to yourself," Wang said.