The U.S. may need to rethink its current North Korea strategy of asking China to step up efforts to rein in an increasingly aggressive Pyongyang as it attempts to become a nuclear power, experts said Wednesday.
That followed another missile launch by the North on Tuesday, which the U.S. confirmed to be an intercontinental ballistic missile (ICBM).
Since taking office, President Donald Trump has tried to get China, North Korea's only major ally, to apply more economic pressure on Pyongyang to help stop its nuclear and missile programs and other acts of defiance against the U.S. and its allies.
Christopher Hill, who was a former U.S. ambassador to South Korea during the George W. Bush administration, and later was ambassador to Iraq under the Obama administration, said Americans will monitor the U.S. response after the latest round of provocations.
"I think the Trump administration, frankly, is not known for long-term thinking, if I can put it kindly," he told CNBC's "Squawk Box" on Wednesday. "In the short run, what they're very concerned about is the possibility that North Korea could have an ICBM that could hit the U.S. with a nuclear weapon. And they have to go and explain that to the American people in 2020 at the elections."
Hill added, "If I were Donald Trump, I wouldn't want to do that. Obviously, he will blame Barack Obama — he does that on everything. But in this case, I think the American people will indeed ask the question you're asking, which is 'what is he going to do about it?'"
Experts agreed that Beijing has been reluctant to apply harsh economic pressure on North Korea because they fear it could destabilize the region. If the current Pyongyang regime were to fall, it could have several effects that might unsettle China, the experts told CNBC on Wednesday.
Josef Jelinek, senior China analyst at the Frontier Strategy Group, told "The Rundown" that "the last thing China wants is a unified Korean Peninsula friendly to the U.S."
He added it could potentially mean U.S. troops at its borders with North Korea. At the same time, a regime collapse could lead to the "potential chaos of refugees destabilizing its own region."
Jelinek said some parties may have 'miscalculated' what China was prepared to do to stop Pyongyang.
"What we've actually seen was a toning down of rhetoric over the last few months," Jelinek said. "President Trump genuinely believed that Xi Jinping would be able to do something to rein in North Korea and I think what's happened is there's been a miscalculation."
After 22-year-old Otto Warmbier, held by North Korea for more than a year, died following his return to the United States, Trump tweeted that while he appreciated China's efforts to help deal with North Korea, it "has not worked out."
In late June, the Trump administration announced its plans to sell Taiwan $1.42 billion worth of arms, and the move predictably irked Beijing. The Treasury Department also unveiled new sanctions on a Chinese company and two Chinese citizens tied to North Korea in response to Pyongyang's weapons program and its disregard for U.N. Security Council resolutions.
Ambassador Hill said that China still could play a key role in tackling the issue, if the U.S. took the time and effort to reassure the mainland.
"I think this is really going to take some time and effort on the part of the Trump administration to convince the Chinese, 'No, the U.S. does not want to put troops up on the Yalu River or a listening post,'" he said.
At the G-20 meeting later this week, it's likely world leaders may decide to push for tougher economic sanctions against North Korea for its ICBM launch. But experts said that applying sanctions was unlikely to deter Pyongyang from pursuing its nuclear ambitions.
Bruce Bennett, a senior defense analyst at the Rand Corp., told CNBC's "Street Signs" on Wednesday, that sanctions weren't likely to become more effective ahead.
"The problem with sanctions is they do almost everything internally and therefore you can't cut off the supply of materials they need by and large, with some minor exceptions," he said.
Restarting talks with Pyongyang is an option that needs to be considered, according to David Wright, co-director of the global security program at the nonprofit science advocacy group Union of Concerned Scientists.
Wright told CNBC's "The Rundown" on Wednesday that the window of opportunity for the U.S. to figure out how to cap North Korea's nuclear ambitions was closing, with Pyongyang continuing to make strides toward long-range missiles that can carry a nuclear warhead.
He said that since sanctions have not worked in the past, that "leaves you with trying to sit down with the North Koreans, trying to talk to them, to lower the temperature around this and to see if there's a way to get them to stop their missile testing, stop their nuclear testing."
Past negotiations had resulted in North Korea temporarily halting its nuclear missile program, Wright added.
Bennett, however, noted that it is unlikely that North Korea will agree to any kind of talks that would include denuclearization as a precondition to opening negotiations.
"North Korea has been absolutely clear about denuclearization. They have said over, and over, and over again that they have no intent to denuclearize. That they plan to maintain their nuclear weapons as essential to survival, regardless of what they're offered in negotiations," he said. "So getting them to give up their nuclear weapons before negotiations is not going to happen."
Wright added that if the U.S. proceeds with talks, it will have to determine what would be the best way to approach the issue — either bilaterally or multilaterally — and determine what they are ready to put on the negotiating table.
"We've heard from North Korean diplomats that North Korea has talked about the willingness to have talks with the United States. I think it's time to find out if they're really serious about that," he said.
— CNBC's Jacob Pramuk contributed to this report.