Pentagon says it is monitoring Chinese spy balloon spotted flying over US

Officials say balloon has been watched for a few days but decided not to shoot it down for safety reasons

The Pentagon has said it is tracking a Chinese spy balloon flying over the US but decided against shooting it down for safety reasons.

Defence officials said the balloon had been watched since it entered US airspace at high altitude a couple of days ago. It has been monitored by several methods including crewed aircraft, and has most recently been tracked crossing Montana, where the US has silo-based nuclear missiles.