The King has said he and Camilla are “filled with immense sadness” by the explosion at an Irish petrol station that killed 10 people.
In a message to the president of Ireland, King Charles sent his “heartfelt sympathy and deepest condolences” over Friday’s incident.
A five-year-old girl and her father were among those who died in what emergency services believe was an accident.
In a statement, the King said: “My wife and I were filled with immense sadness when we heard of that appallingly tragic explosion at Creeslough, County Donegal…
“However inadequate this may be under such shattering circumstances, we wanted you to know that our most heartfelt sympathy and deepest condolences are with those families and friends who have lost their loved ones in this devastating tragedy, together with yourself and the people of Ireland.”
He also recalled “with the greatest fondness” meeting people from across Donegal during a 2016 visit.
The explosion devastated apartments next to the petrol station and police have released the names of those killed.
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Among them are Shauna Flanagan Garwe and her father Robert Garwe, 50, who had popped into the petrol station to buy a birthday cake for the five-year-old’s mum.
Catherine O’Donnell, 39, and her 13-year-old son James Monaghan are also among the dead.
The other six victims are James O’Flaherty, 48, Jessica Gallagher, 24, Martin McGill, 49, Hugh Kelly, 59, Martina Martin, 49, and 14-year-old Leona Harper.
A man in his 20s is in a critical condition in hospital in Dublin, while seven others are being treated at Letterkenny University Hospital and are described as stable.
Emergency services have praised locals who dug through debris to help first responders in the wake of the blast.
The regional chief ambulance officer, JJ McGowan, told RTE News: “They were doing momentous work. People in flip-flops, shorts, T-shirts removing rubble and debris.”
Police superintendent Liam Geraghty said on Sunday that the scene of the explosion was still being examined and remains cordoned off.
Post-mortem examinations have started and will continue over the next few days, although results will not be released for “operational reasons”.
Mr Geraghty said: “It is a huge impact for a small rural community – they were all local people, all very much involved in the community, all shopping in their local shop.
“But it is a very strong community, as seen here on Friday afternoon… so I’m sure the community will come together and will support each other.”