SHANGHAI — A United States citizen died from the coronavirus in Wuhan, China, American officials said on Saturday. It was the first known American death from the illness, and was likely to escalate diplomatic tensions over Beijing’s response to the epidemic.

Few details about the American, who died on Thursday, were immediately available. According to the United States Embassy in Beijing, the person was around 60 years old and died at Jinyintan Hospital in Wuhan, the inland metropolis at the center of the epidemic. Two people familiar with the matter said the person was a woman and had underlying health conditions.

The United States government has been evacuating many of its diplomats and other citizens from Wuhan, which the Chinese authorities have locked down in an effort to contain the spread of the virus. It could not immediately be learned whether the American who died had tried to leave the city on any of the flights organized by the State Department.

Word of the death emerged as frustrations about Beijing’s handling of the epidemic, which has already provoked outrage and criticism within China, were beginning to emerge at the diplomatic level as well. The virus has killed at least 700 people in China, sickened thousands more and spread across the globe.

For more than a month, the United States Centers for Disease Control and Prevention have been offering to send a team of experts to China to observe the outbreak and help if possible. But no invitation has come.

The World Health Organization, which made a similar offer about two weeks ago, appeared to be facing the same cold shoulder, though a spokeswoman said it was just “sorting out arrangements.”

Current and former health officials and diplomats said they believed the reluctance came from China’s top leaders, who do not want the world to think they need outside help.

Within China, public discontent about the government’s response to the crisis reached an extraordinary new peak on Friday after the death of Dr. Li Wenliang, who had warned his colleagues early on about the new virus but was reprimanded for spreading rumors.

After Dr. Li’s death, grieving internet users posted messages expressing anger about the way he had been treated and even demanding freedom of speech — unheard-of in China’s authoritarian political system.

Communist Party officials said on Friday that they would send a team from the powerful anticorruption committee to investigate the circumstances surrounding Dr. Li’s death. Chinese state news media also reported on Saturday that the government was sending two senior officials to Wuhan to reinforce efforts to bring the outbreak under control.

It was not immediately clear if the appointments on Saturday amounted to a reshuffling of the local leadership or were simply an effort to reinforce officials on the front line. Still, it appeared to be an acknowledgment that the authorities in Wuhan had been overwhelmed.

Japan also said on Saturday that one of its citizens had died in a Wuhan hospital from a suspected case of the coronavirus. But the Japanese Foreign Ministry said that based on information it received from the Chinese authorities, it could not confirm whether the man, who was in his 60s, had been infected with the new virus. The ministry called the cause of death viral pneumonia.

As the new coronavirus spreads, China is confronting a growing sense of isolation — a stark reversal for the country after decades of economic and diplomatic integration with the rest of the world. Many countries, including the United States, have placed entry restrictions on travelers from China. Airlines have canceled flights. Fears of the virus have fueled anti-Chinese racism in some parts of the world.

Mr. Pompeo said that the United States was prepared to spend up to $100 million in existing funds to help China and other countries fight the epidemic. Mr. Pompeo also said that the State Department had helped transport about 18 tons of donated medical supplies, including masks, gowns and gauze, to the people of China in the past week.

Mr. Trump praised China’s handling of the crisis on a phone call with China’s top leader, Xi Jinping, on Friday. And in a pair of Twitter posts, Mr. Trump said Mr. Xi was leading “what will be a very successful operation.”

But other American officials have quietly voiced concerns about China’s response to the epidemic. And the confirmation on Friday that repeated offers of help to China had been ignored only deepened the sense of worry.

Alex Azar, the United States secretary of health and human services, said at a news briefing on Friday that he had recently reiterated the C.D.C. offer to his Chinese counterpart, Dr. Ma Xiaowei.

Asked about the holdup, Mr. Azar said: “It’s up to the Chinese. We continue to expect fully that President Xi will accept our offer. We’re ready and willing and able to go.”

Motoko Rich and Hisako Ueno contributed reporting from Tokyo, and Steven Lee Myers from Beijing. Claire Fu contributed research.