The first rejection of a U.N. Security Council resolution aimed at bolstering sanctions on North Korea may prompt leader Kim Jong Un to give the go-ahead for the country's seventh nuclear test in the not-so-distant future.

As the international community has failed to thwart Pyongyang's nuclear and ballistic missile ambitions, Kim is likely to step up development of strategic weapons without hesitation to confront the United States and its allies including South Korea.

Diplomatic sources warn North Korea would greatly jeopardize global security, given that the purpose of its military strength has changed with the world being apparently divided into two groups -- Western democratic nations and what they call autocratic countries.

North Korean leader Kim Jong Un is pictured at an emergency meeting of the Politburo of the Central Committee of the Workers' Party of Korea on May 15, 2022. (KCNA/Kyodo)

On Thursday, China and Russia, which have been deepening ties with North Korea, vetoed the latest U.S.-drafted resolution distributed to Security Council members last month following Pyongyang's firing of an intercontinental ballistic missile in March.

This was the first rejection of a U.N. Security Council resolution designed to prevent North Korea from developing nuclear weapons and missiles since 2006 when the first sanctions were adopted, underscoring the dysfunction of the United Nations.

One of the sources said, the Security Council has been "already dead" since Russia attacked Ukraine on Feb. 24, as Moscow, one of the veto-wielding members, has been "trying to use the U.N. work as a means to counter the United States."

Sino-U.S. tensions have also been intensifying over many issues such as China's alleged unfair trade practices, human rights violations in Hong Kong and Xinjiang, as well as security challenges to Taiwan, which Beijing considers as part of its territory.

China and the Soviet Union, Russia's predecessor state, were competitors during the Cold War, as they were at loggerheads over interpretations and practical applications of Marxism-Leninism, the ideology of 20th-century communism.

But the two of the five U.N. Security Council permanent members have reinforced economic and security relations in recent years to tackle the post-Cold War international order dominated by Western democratic countries.

At the Security Council meeting on Thursday, China said additional sanctions against North Korea will "only lead to more negative effects," while Russia claimed they would be "extremely dangerous from humanitarian consequences."

Indeed, North Korea's economy is believed to be facing a serious downturn due largely to a plunge in trade with China, Pyongyang's most influential ally, in the wake of a border blockage imposed after the novel coronavirus raged in the neighboring nation in early 2020.

On May 12, North Korea reported its first COVID-19 case since the pandemic began. As all cities and counties have been thoroughly locked down across the country, fears are growing that its citizens cannot procure adequate food and daily necessities.

"I don't know whether China and Russia are really concerned about the domestic humanitarian situation in North Korea, but the rejection of the resolution indicated they are willing to invite Kim to their camp to resist the U.S.-led bloc," the source said.

"Without strong opposition by China and Russia, Kim can do whatever he wants whenever he wants," he added.

North Korea had refrained from firing an ICBM for the past few years, as China and Russia had called on the United States to relieve economic sanctions on Pyongyang on the grounds that it had suspended nuclear and long-range ballistic missile tests.

In January, however, Pyongyang said it might resume all "activities" it had temporarily suspended to build trust with then U.S. President Donald Trump, President Joe Biden's predecessor, while urging Washington to change its "hostile policy."

Since early this year, North Korea has conducted a spate of weapons tests, as direct talks between Pyongyang and Washington on denuclearization and sanctions relief have been at a standstill for more than two years.

On March 24, Pyongyang made the first launch of an ICBM since November 2017, marking an end to its self-imposed moratorium on such firings that had dated back to April 2018.

Also on Wednesday, North Korea fired three missiles, including one capable of intercontinental range, off its east coast, a day after Biden ended his first trip to South Korea and Japan -- two of the closest U.S. allies in East Asia -- since taking office.

Jeff Kingston, director of Asian Studies at Temple University Japan in Tokyo, said Kim does not "expect sanctions relief" but he "misses the Trump hoopla and wants Biden to engage to show everyone that North Korea is a power to be reckoned with."

Another diplomatic source said a North Korean nuclear test is "just around the corner" but this "would not be aimed to bring Washington back to the negotiating table."

Recently, Kim has reiterated his readiness to "pre-emptively" use the nation's nuclear weapons if the country is threatened by what it regards as "hostile forces."

"Kim appears to be becoming more eager to join hands with China and Russia to fight against the United States. North Korea's next nuclear test may herald the beginning of a new Cold war," the source said.