Last Updated Jan 6, 2016 12:06 PM EST
While the U.S. is still investigating North Korea's claims that it conducted a hydrogen bomb test Wednesday, Marco Rubio became the first of the 2016 candidates to respond.
"I have been warning throughout this campaign that North Korea is run by a lunatic who has been expanding his nuclear arsenal while President Obama has stood idly by," he said in a statement. "If this test is confirmed, it will be just the latest example of the failed Obama-Clinton foreign policy."
During an Iowa campaign stop later that day, the Florida senator called North Korean leader Kim Jong Un a "lunatic" and "dangerous."
"This administration has done nothing about it. And Bill Clinton wanted to give speeches in North Korea a few years ago, by the way," Rubio said. "It's reckless what's happened under this administration and what happened under Hillary Clinton's watch at the State Department."
Rubio also called on the U.S. to put North Korea back on the list of state sponsors of terrorism. (President George W. Bush officially removed the country from the list in 2008.)
Other 2016 contenders have joined in to bash the president and former secretary of state, with ex-Hewlett Packard executive Carly Fiorina deeming North Korea "yet another Hillary Clinton foreign policy failure" and New Jersey Gov. Chris Christie blaming the president for "playing footsie with the Iranians" and thus allowing Pyongyang to further their nuclear ambitions.
GOP candidate and former Florida Gov. Jeb Bush tweeted out his concerns that the bomb claim was only continuing a "feckless Obama/Clinton foreign policy":
Republican rival Donald Trump also weighed in on the test Wednesday, calling on China to get involved in dealing with "the North Korea problem."
"Nobody is discussing it with China," Trump said in an interview with Fox News. "China has total control, believe me. They say they don't. They have total control over North Korea. And China should solve that problem. And if they don't solve the problem, we should make trade very difficult for China. Because we are -- believe it -- we are holding China up."
Former neurosurgeon-turned-politican Ben Carson, in an interview with the Des Moines Register, added that "in order to keep [Kim John Un] under control, I think we need to work with China" because "China is really their lifeline."
He also proposed "re-imposing severe sanctions" on North Korean when their leader "does things he's not supposed to do."
Carson further pointed out that the U.S. should reinvest in its space program to stay technologically relevant, saying the nation has already "largely abandoned our space program."
"In the future, he who controls space will control earth," he said.
Democratic presidential candidate Bernie Sanders seemed to align with Trump in the push for China to concern itself with the bomb test out of Pyongyang.
"We're going to have to lean on China," Sanders told ABC News early Wednesday. "China is North Korea's closest ally and they're going to have to push North Korea to start adhering to international agreements."
Sanders, calling North Korea a "paranoid isolated nation," added that China is "equally concerned" about the country's nuclear power.
"When you have a hydrogen bomb -- if that's true -- you are a threat to China as well," he said.
In a statement Wednesday, Democratic front-runner Hilary Clinton called for the United States and its partners to "immediately impose additional sanctions against North Korea."
Billing the nuclear test, if verified, as a "provocative and dangerous act," the former secretary of state added that the U.S. should not give in to North Korea's "bullying" and "blackmail."
She further pushed the Chinese government to be "more assertive" and proposed the U.S. and its allies work to "strengthen our missile defenses."
If the test of a "miniaturized" hydrogen bomb is confirmed, it would put Pyongyang a big step closer to improving its still-limited nuclear arsenal.
The North Koreans deemed the test a "perfect success."
Pyongyang also claimed the test was "conducted in a safe and perfect manner" and "had no adverse impact on the ecological environment."
However, Seoul's intelligence agency said the device may not have been a hydrogen bomb, South Korea's Yonhap News Agency reported, according to Reuters news agency. South Korea's meteorological agency said it hadn't detected any radiation after the supposed test, Reuters added.
Japan's government also said its environmental detectors noted no radiation after the claimed test.
The test, if confirmed by outside experts, would lead to a strong push for new, tougher sanctions at the United Nations and further worsen already abysmal relations between Pyongyang and its neighbors.
The U.N. Security Council tentatively set an emergency meeting for Wednesday morning to take up the possible test .
North Korean nuclear tests worry Washington and others because each new blast is seen as pushing North Korea's scientists and engineers closer to their goal of an arsenal of nuclear-tipped missiles that can reach the United States.
While a hydrogen bomb is much more powerful than an atomic bomb, it is also much harder to make. In a hydrogen bomb, radiation from a nuclear fission explosion sets off a fusion reaction responsible for a powerful blast and radioactivity.
Pyongyang says its nuclear weapons program is necessary to defend itself against the United States. North Korea under leader Kim Jong Un has pledged to bolster its nuclear arsenal unless Washington scraps what Pyongyang calls a hostile policy.
Washington sees North Korea's pursuit of nuclear weapons and ballistic missiles as a threat to world security and to its Asian allies, Japan and South Korea.
The test comes amid failed diplomatic efforts to persuade the North to give up its nuclear ambitions. Six-nation negotiations on dismantling North Korea's nuclear program in exchange for aid were last held in late 2008 and fell apart in early 2009, when North Korea was led by Kim Jong Un's father, Kim Jong Il, who died in late 2011.