A search operation in Ballybofey has been stood down for the night.
The Irish Coast Guard's 118 rescue helicopter was engaged in the search, which focused on an area of the River Finn.
The Coast Guard chopper arrived in the Twin Towns skyline just after 5.30pm after concerns were raised on Monday afternoon about the safety of a local woman.
Gardai and emergency services were also at the scene, while groups of locals gathered on the bridge and on the river bank to assist the agencies.
The Coast Guard are leading the operation, which will resume at first light on Tuesday.
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