South Eastern Health Trust in Facebook appeal for staff help
Part of the health service in Northern Ireland has appealed on social media for its off-duty staff to work to ease pressure on its emergency departments.
The South Eastern Health Trust said its hospitals are under pressure after an extremely busy Christmas period.
It said the number of patients attending its emergency departments this winter has been "unprecedented".
It made the appeals for extra staff on Facebook and Twitter on both Monday and Tuesday.
BBC News NI's health correspondent Marie-Louise Connolly described the move as "highly unusual".
The trust runs several hospitals, including the Ulster Hospital in Dundonald, County Down, and the Lagan Valley Hospital in Lisburn, County Antrim.
It said its emergency departments were "incredibly busy, like any others in Northern Ireland at the moment".
A spokeswoman said the trust contacts staff "internally" to ask them to work at times of need.
But she added that it uses appeals on social media appeal as a "back-up", and the method is part of the trust's "winter pressure contingency plan".
The South Eastern Health Trust is not the only one to feel strain on its resources over the Christmas and new year holiday.
Last week, Londonderry's Altnagelvin Hospital in the Western Health Trust implemented an emergency plan to cope with the number of patients with which it was dealing.
On Boxing Day, doctors in the Southern Health Trust said patients were having to wait for up to 34 hours to speak to an out-of-hours GP.
The trust sent a text message to its off-duty doctors, asking them to help.
In the text, the trust said its out-of-hours service was "under unprecedented pressure".