At a news briefing in Washington on Tuesday, Alex M. Azar II, the secretary of health and human services — who had just reiterated the offer of scientific and logistical assistance — said he was “delighted” that China was accepting.

The Chinese authorities agreed to work with experts from other countries after a meeting between President Xi Jinping and Dr. Tedros Adhanom Ghebreyesus, director general of the W.H.O.

The W.H.O. praised China’s response to the outbreak, including its rapid identification of the virus and its “openness to sharing information with W.H.O. and other countries.”

Though the outbreak is continuing in China, federal officials maintained that the risk of infection remains low in the United States.

“Right now, there is no spread of this virus in our communities at home,” Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, said at the news briefing.