China's ceremonial parliament has accused American lawmakers of trampling on the sovereignty of other nations after the US passed a measure condemning a suspected Chinese spy balloon's intrusion into US airspace.

The statement issued on Thursday by the National People's Congress's Foreign Affairs Committee repeated Beijing's insistence that the balloon was an unmanned civilian weather research airship, a claim the US has dismissed citing its flight route and payload of surveillance equipment. While China at first expressed regret over the February 4 incident, it has toughened its rhetoric in a further sign of how badly relations between the sides have deteriorated in recent years.