OSLO (Reuters) -A U.S. military aircraft with four people on board has crashed in northern Norway, local police and the country's Joint Rescue Coordination Centres (JRCC) said on Friday.

       The MV-22B Osprey aircraft belonging to the U.S. Marine Corps was taking part in a NATO military exercise called Cold Response when it was reported missing at 1826 CET (1726 GMT), the JRCC said.

       A rescue helicopter and a Norwegian military Orion plane searching the area spotted the wreckage from the air at 2017 GMT after receiving an emergency signal.

       "We've discovered an aircraft that has crashed. We've seen no sign of life," Nordland police chief of staff Bent Eilertsen told Reuters.

       "We've been told it's an American aircraft with four Americans on board," he said.

       Because of the bad weather, the rescue aircraft could not land. Instead, police and rescue services were trying to reach the site by land, but it was unclear how long this could take.

       "It's dark, the weather conditions are bad and there is a risk of avalanches," Eilertsen said.

       The plane was on a training exercise and had been due to land at around 1800 CET (1700 GMT). Weather was bad in the area, with conditions worsening.

       (Reporting by Gwladys Fouche and Terje Solsvik; editing by Grant McCool and Sandra Maler)