It is bitterly cold in Latvia and sub-zero temperatures overnight mean there is little hope of finding any more survivors in the rubble of the Riga supermaket, whose collapse has now claimed 52 lives.

Twenty-two people are still in hospital, and several are still missing.

“We have reached the most difficult phase of the rescue operation. We now have to clean that part of the building which is still covered by roof, but the whole construction is very fragile,” said Intars Zitans, the deputy head of the state rescue and firefighting service.

The rubble is some two and a half metres deep in places, but search operations had to be called off for a while early on Saturday as part of the damaged roof collapsed. The structure had to be stabilised before the search could resume.

Tributes are piling up outside as people bring candles and flowers. A criminal investigation has been opened into the accident, which has shaken the entire country. Latvia is observing its second day of official mourning.