The search off the coast of Co Donegal for a missing diver is expected to continue on Monday.
They added that sea conditions are calmer today compared to yesterday when five metre swells hampered the search mission in "challenging conditions".
The diver is believed to be one of a number who were diving in wrecks in the area and was reported missing to Malin Head Coast Guard at 7pm this evening.
The Sligo-based 118 helicopter, Lough Swilly Lifeboat and up to four local boats are involved in the search.
The alarm was raised on Saturday night when the walker had not returned to his vehicle.
He was last seen up in the Slieve Snacht area and Donegal Mountain Rescue as well as the crew from Rescue 118 are assisting in the search.