BEIJING (AP) — Chinese officials say the coronavirus epidemic isn’t over in their country and that daunting challenges remain.

Foreign ministry spokeswoman Hua Chunying said Tuesday that authorities need to make sure that infected people arriving from abroad don’t spread the disease and start new outbreaks.

She hit back at U.S. criticism of her country’s handling of the epidemic, saying that China and the U.S. should work together to fight it.

“We also hope that some U.S. officials can follow through in the spirit of the two heads of states’ call and create more favorable conditions for the two countries to cooperate in the fight against the disease,” she said. The two leaders talked late last week.

Hua noted that some local Chinese governments and companies have provided virus-related medical supplies to the United States, even as the demand for those supplies remains high in China.