Latvia begins three days of mourning for supermarket tragedy victims Three days of national mourning have begun in Latvia to remember the victims who died when a supermarket roof caved in on top of them. It happened in the Latvian capital, Riga, on Thursday evening as crowds of shoppers were buying groceries after work. Rescue workers stop periodically to listen for survivors and the sound of mobile phones ringing in the wreckage. Nils Usakovs, Mayor of Riga, speaking at the scene on Friday night, said the operation would take a long time. It looks like they will have to work at least the whole next day and probably until Sunday evening. Because you have to understand that the whole task is complicated, all the pieces are heavy, on average 7 and a half tonnes per piece. And, in average it takes 15 minutes, up to half an hour, to get rid of one piece," said Usakovs. Andrejs Ozolins, one of the fire fighters searching for survivors, said: "We will continue rescue operations and we will carry on searching for the missing for as long as it takes. There is still hope that some people have survived. Now we are clearing the area of the ruins. The reason for the collapse is still not known. Officials said workers had been building a garden and children's playground on the roof. Relatives of the victims have been told they will receive compensation from the Latvian state. Maxima Group, the biggest retailer in the Baltic states, runs 500 supermarkets in the region.