HONG KONG — China warned on Friday that tensions on the Korean Peninsula could run out of control, after North Korea said it could test a nuclear weapon whenever its top leader, Kim Jong-un, decided, and as an American naval group neared the peninsula in a show of resolve.
“The United States and South Korea and North Korea are engaging in tit for tat, with swords drawn and bows bent, and there have been storm clouds gathering,” China’s foreign minister, Wang Yi, said in Beijing, according to Xinhua, the state news agency.
“We urge all sides to no longer engage in mutual provocation and threats, whether through words or deeds, and don’t push the situation to the point where it can’t be turned around and gets out of hand,” Mr. Wang said after meeting with his visiting French counterpart, Jean-Marc Ayrault, according to Xinhua.
“No matter who it is, if they let war break out on the peninsula, they must shoulder that historical culpability and pay the corresponding price for this,” Mr. Wang said.
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.
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.
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 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 of its 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 capability 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, all major candidates in the presidential election next month 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 North Korean Foreign Ministry’s Institute for Disarmament and Peace.
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 to 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 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 the North Korea are neighbors with traditional friendly ties, including normal trade activities,” a spokesman for the Foreign Ministry, Lu Kang, told reporters on Thursday. “We strongly hope that all parties concerned will not pin all their hopes on sanctions only.”
Gerry Mullany reported from Hong Kong, and Chris Buckley from Beijing. Choe Sang-Hun contributed reporting from Seoul, South Korea.