His comments were the bluntest this week from China, which has been trying to steer between the Trump administration’s demands for it to do more to stop North Korea’s nuclear weapons program and its longstanding reluctance to risk a rupture with the North, its neighbor and longtime partner. In a phone conversation with Mr. Trump on Wednesday, China’s president, Xi Jinping, also called for restraint.
The North Korean military issued a statement on Friday threatening to attack major American military bases in South Korea, as well as the presidential Blue House, warning that it could annihilate those targets “within minutes.”
The statement also denounced what it called the Trump administration’s “maniacal military provocations,” like threats of possible unilateral action coming from Washington and the deployment of warships in waters near the Korean Peninsula.
“Nothing will be more foolish if the United States thinks it can deal with us the way it treated Iraq and Libya, miserable victims of its aggression, and Syria, which did not respond immediately even after it was attacked,” a spokesman of the General Staff of the North’s People’s Army said in a statement carried by its official Korean Central News Agency.
Analysts say recent satellite images from North Korea suggest that it might soon carry out another underground detonation, despite pointed warnings by the United States not to do so.
On Saturday, the North marks the 105th anniversary of the birth of its founder, Kim Il-sung, and it often uses such occasions as an opportunity to show off its military advances. The country said it could test a nuclear weapon whenever its current leader, Kim Jong-un, decided.
With a United States Navy strike group led by the aircraft carrier Carl Vinson diverted to the region, North Korea’s vice minister, Han Song-ryol, said on Friday that the United States was “becoming more vicious and aggressive” under President Trump and that “we will go to war if they choose.”
Mr. Han said whether North Korea holds another nuclear test would be “something that our headquarters decides.” But he added an ominous coda: “At a time and at a place where the headquarters deems necessary, it will take place.”
Mr. Han’s remarks, made to The Associated Press, typified the often bellicose language of the North’s leaders and its state news media. But as Pyongyang’s weapons technology rapidly advances and the United States is led by an unpredictable new president, some of its neighbors were examining worst-case scenarios.
The Japanese news media reported that the government’s National Security Council had been discussing the possible evacuation of an estimated 57,000 Japanese citizens in South Korea, should war break out. “We will take all necessary steps to protect our people’s lives and assets,” said Yoshihide Suga, Japan’s chief cabinet secretary. The Kyodo news agency said the council was concerned about the possibility of North Korean refugees arriving in boats on its shores.
Prime Minister Shinzo Abe of Japan expressed concern on Thursday that North Korea could have the ability to deliver missiles equipped with sarin, the nerve agent whose recent use against civilians in Syria prompted Mr. Trump to order a missile strike there.
Russia, another neighbor of North Korea, echoed China in urging all parties on Friday to exercise caution. A Kremlin spokesman, Dmitri S. Peskov, called on “all the countries to refrain from any actions that could amount to provocative steps,” Reuters reported.
In South Korea, whose people have lived through saber-rattling involving the North for decades, there were few signs of panic. Nonetheless, the South Korean Foreign Ministry warned on Friday that if the North conducted another nuclear test or launched an intercontinental ballistic missile, it would suffer an “unbearably strong punishment.” All the major candidates in the presidential election set for next month have called on the United States not to do anything that might initiate war on the peninsula without first seeking the consent of South Korea, its military ally.
Further raising fears was a report by NBC News that the United States was prepared to take pre-emptive military action against North Korea if it became convinced that the North was preparing to test a nuclear weapon. The report, which cited unidentified intelligence officials, was vigorously denied by people in the Trump administration. The Defense Department said only that it would not “publicly speculate on possible scenarios.”
Alluding to the Trump administration’s decision to send a naval flotilla to the region, North Korea accused the United States of introducing “nuclear strategic assets” to the peninsula and “pushing the situation there to the brink of war.”
“This has created a dangerous situation in which a thermonuclear war may break out any moment on the peninsula,” said a statement attributed to the Institute for Disarmament and Peace of the North Korean Foreign Ministry.
As North Korea celebrates its founder’s birthday with what is expected to be a large military parade in Pyongyang, the capital, this weekend, Vice President Mike Pence will be headed to South Korea, starting a 10-day tour of the region on Sunday, with the North expected to be a prime topic.
In his remarks in Beijing, Mr. Wang said there was still hope for renewed negotiations with North Korea on its weapons program. “There can also be flexibility about the form of renewed talks,” he said. “As long as there’s dialogue, formal or informal, first-track or second-track, bilateral, trilateral, quadrilateral, China is willing to support this.”
The United States has said it will not negotiate with the North unless it first shows that it is serious about ending its nuclear arms program and not merely playing for time.
China hosted multinational talks during the 2000s aimed at ending the North’s pursuit of nuclear weapons and it has voted in favor of United Nations sanctions to punish Pyongyang for continuing its weapons development. But Chinese trade and aid have remained a lifeline for the North Korean economy and so far, Beijing has been reluctant to sever economic ties there.
Two months ago, China announced it had suspended coal imports from North Korea. But while those coal shipments seem to have dried up, Chinese overall trade with North Korea has remained robust. On Thursday, China revealed that its trade with North Korea grew 37.4 percent in the first quarter of 2017, compared with the same period in 2016.
Chinese news outlets reported on Friday that Air China, the country’s main international airline, would suspend flights to Pyongyang starting on Monday, leaving only Air Koryo of North Korea operating flights between Pyongyang and Beijing or other Chinese cities. The move appeared to have been in the works for some time; NK News, a website about North Korea, reported last month that the suspension was likely, saying that Air China’s services were underused and that its flights were often canceled.
The Chinese Foreign Ministry said this week that the Trump administration should not expect China to risk instability in North Korea by going along with choking sanctions.
China and North Korea are “neighbors with traditional friendly ties, including normal trade activities,” a spokesman for the Foreign Ministry, Lu Kang, told reporters on Thursday.
He added, “We strongly hope that all parties concerned will not pin all their hopes on sanctions only.”