Strange things are happening in the sky above the USA. Fighter jets have shot down four balloons. Officials said the balloons were a danger to airplanes. They were flying at an altitude of around 12,200 metres. The White House said the balloons were not linked to aliens. A spokesperson said: "I don't think the American people need to worry about aliens with respect to these crafts." Earlier, an official said aliens could not be counted out.

The USA and China sent each other tit-for-tat messages. The US believes the balloons are spy balloons. There is no proof of this. Experts are looking at the electronics from the balloons. China said the balloons were for tracking weather, not for spying. Beijing said American balloons have flown in China's airspace over ten times in the past year. The USA said this was untrue. The US Secretary of State cancelled a visit to China because of the balloons.