A man has gone missing from an offshore installation around 100 miles south-east of Aberdeen.
Rescuers have been searching for the 50-year-old man after the alarm was raised at after 9pm on Sunday evening.
Two oil supply vessels, a Coastguard helicopter and Coastguard aeroplane were involved in the search, the Coastguard said.
The search operations were stood down at 7am on Monday.
Rig owner Valaris say the man’s family have been informed and a helpline has been set up for other concerned relatives.
The firm also confirmed that the remaining 53 personnel on board have all been accounted for.
The installation from which the person was reported missing is around 100 miles south-east of Aberdeen.
A Valaris spokesperson said: “Valaris regrets to confirm that a Valaris employee was reported missing from jackup VALARIS 121.
“The safety of all personnel is Valaris’ top priority, and the company’s emergency response procedures were activated immediately after the incident was reported. Searches from the air and sea involving aircraft from HM Maritime and Coastguard Agency, as well as vessels in the area, were conducted through the night.
“The missing employee’s family has been informed of the development, and the company is providing them with support.
“A dedicated phone line has been set-up for any other concerned relatives. The number to call is 01224 548 527.
“At the time of the incident being reported, the rig was under tow from its last operating location in the UK North Sea to the port of Dundee, UK.
“The company will be making no further comment at this time.”
A Police Scotland spokesperson said: “Around 9.20pm on Sunday, January 22, officers received a report of a 50-year-old man missing from an oil rig in the North Sea.
“Police are liaising with partner agencies to establish the full circumstances.”