HONG KONG — China urged calm Friday and said that it was looking into reports of a high-altitude surveillance balloon suspected of belonging to Beijing hovering over the United States, while Canada said it was monitoring a “potential second incident.”

U.S. officials said Thursday the military was monitoring the balloon, which flew over the Aleutian Islands and through Canada before being spotted Wednesday over Billings, Montana. A senior defense official said the U.S. was confident that the balloon belonged to China, which has flown stratospheric balloons over the country before but not usually for this long.

Chinese Foreign Ministry spokesperson Mao Ning said Beijing was assessing the situation and that speculation and hype were unhelpful while facts were still being clarified.

“China is a responsible country that always abides by international law and has no intention of infringing on any country’s territory and airspace,” Mao said at a daily briefing.

“We hope that both sides can handle this together calmly and carefully,” she added.

The balloon revelation comes days before Secretary of State Antony Blinken is due to visit China, the highest-ranking Biden administration official to do so. Mao said she had no information on whether his visit would be affected.

Feb. 3, 202301:10

In a brief statement late Thursday, the Canadian Department of National Defence said a high-altitude surveillance balloon had been detected and was being “actively tracked” by the North American Aerospace Defense Command, a U.S.-Canadian military organization. It did not provide details about the balloon or say whether it was the same balloon detected in the U.S.

“Canadians are safe and Canada is taking steps to ensure the security of its airspace, including the monitoring of a potential second incident,” it said, without elaborating.

The statement, which did not mention China, added that Canadian intelligence agencies were working with U.S. partners to protect against “foreign intelligence threats.”

The department did not immediately respond to phone calls and emails requesting additional information.

The senior defense official said Thursday the balloon was still over the U.S. but declined to say where. It has not been shot out of the sky so far, U.S. officials said, because falling debris could pose a safety risk to people on the ground. They said the balloon was of limited use in collecting intelligence and did not pose a threat to civil aviation.

Chinese experts raised questions about the origin of the balloon in an article Friday in The Global Times, a state-backed nationalist tabloid. Liu Ming, head of the science and technology intelligence company MizarVision, said that images released by U.S. officials appeared to show a balloon that was incapable of traveling such long distances or with such precision.

Military expert Zhang Xuefeng told the newspaper that the U.S. would not necessarily be able to identify the balloon’s country of origin while it was still in the sky, and that it was pointless for China to use balloons to spy on the continental U.S. when it has a much more effective satellite network.

“It is recommended that the United States shoot down the balloon and find some clues before blaming other countries,” Zhang said.

Isaac Lee, Courtney Kube, Carol E. Lee and Yixin Wang contributed.