Latvia's prime minister resigned on Wednesday, in the wake of a supermarket roof cave-in that killed 54 people, just weeks before the country enters the eurozone.
The political thunderbolt announced by Prime Minister Valdis Dombrovskis effectively put an end to Latvia's government.
Latvian President Andris Berzins said he would "begin negotiations on the formation of a new government next week", ruling out an immediate election. The next parliamentary elections are set for October 2014.
The November 21 store collapse was Latvia's worst-ever peacetime disaster, leaving the Baltic state of two million people reeling.
"Considering the tragedy and all related circumstances... a new government is needed that has the clear support of parliament," Dombrovskis told reporters as he fought back tears.
"Therefore I have submitted my resignation from the post of prime minister," he said after a meeting with Berzins.
Latvia enters the eurozone on January 1, an unpopular move that Dombrovskis made a policy cornerstone for his administration.
He insisted ON Wednesday that euro adoption played no part in his decision to leave and denied media speculation Berzins had demanded he step down.
"I've given a great deal of thought to the political and moral consequence of what happened," Dombrovskis said referring to the disaster, adding would stay on as a care-taker prime minister until a new administration was formed.
Dombrovskis said that although he was not prepared to head another government himself, he wanted his centrist Unity party to be part of the future governing coalition.
"I'll probably resume my duties as a member of parliament but that matter requires more thought," he added, without elaborating.
Analysts said Wednesday his surprise resignation only ramped up political instability as the country is poised for a currency switch.
"It's going to create a certain amount of chaos. Most probably Latvia will join the eurozone with a caretaker prime minister in charge," analyst Ivars Ijabs of the University of Latvia said.
"The next coalition most probably will be the same (as the existing one) but with the addition of the Greens and Farmers' Union," he said.
"But no-one really knows. I spoke to a couple of politicians an hour ago and they didn't know," he said, adding Dombrovskis had "no clear successor."
The 42-year-old physicist, respected for his squeaky clean politics, was Latvia's longest-serving prime minister since it won independence from the crumbling Soviet Union in 1991.
Berzins and top security officials are to meet on December 4 to discuss the fallout from last week's deadly collapse.
Questions and tears
Fifty-four people died and 40 others were injured when the roof of a Maxima supermarket came crashing down last week in the Zolitude suburb of the capital Riga.
Early on Wednesday, hundreds of Latvians braved the bitter cold to pay their respects to the three firefighters killed in the disaster.
Sirens rang out across the city as their coffins emerged from the Dome Cathedral in Riga's old town.
Firemen Edgars Reinfelds, Sergejs Iziks and Vilnis Steinitis – aged 25, 44 and 36 respectively – died when another part of the roof collapsed while they searched for victims of the first cave-in.
Clutching a bouquet of white lilies, parliamentary speaker Solvita Aboltina shivered as she told AFP: "We need to do everything in our power to make sure no one else has to die for us in this way."
The premier's resignation comes amid growing pressure to find the cause of the collapse, with debate focused on whether sub-standard materials were used in construction or if the award-winning project contained a design flaw.
The central government and city council have each announced separate investigations into the disaster.
The Maxima supermarket chain is also facing tough questions.
It initially claimed to have been leasing the building but has now admitted to owning it, apparently via a complex system of offshore holding companies.