As public fury mounted Thursday along with the casualty toll in what officials were describing as Turkey’s deadliest mine accident, Prime Minister Recep Tayyip Erdogan found himself on the defensive after a seemingly tone-deaf response to the disaster.

The number of confirmed dead rose to 283, the state-run Anatolia news agency reported, citing Energy Minister Taner Yildiz. Outside the town of Soma in western Turkey, the families of miners still missing kept an anguished vigil, even as prospects dimmed for finding any survivors.

A major labor confederation called a strike in response to the disaster, and Turks again took to the streets to protest safety lapses in the mine complex. Many dressed in black to represent the smoke and coal dust on the bodies pulled from the mine.

Yildiz said Thursday morning that no one had been found alive in the previous 12 hours. About 140 miners were still unaccounted for. Throughout the day Wednesday, relatives and others sobbed or looked on numbly as one body after another was borne up out of the depths.

On Thursday, the pace of recovery slowed as rescuers sought to penetrate more remote areas of the maze of tunnels. Harrowing stories emerged of the miners’ desperate attempts to survive the catastrophic underground fire that broke out Tuesday afternoon.

Fourteen miners who initially survived found shelter in a cramped underground “refuge room,” but all died after apparently sharing an insufficient supply of oxygen stored in the room, rescuers told the Hurriyet newspaper.

The government has declared three days of mourning for the victims of the fire, which is thought to have been sparked by an explosion in a power distribution unit. The government has said that 383 people were rescued from the mine, many with injuries.

Yildiz told reporters Thursday morning that the fire had not yet been extinguished, and he said most of the deaths resulted from carbon monoxide poisoning.

The Soma disaster cast a spotlight on the harsh and dangerous working conditions Turkish miners face and raised questions as to whether cozy relationships between mine owners and the government had quashed stricter safety standards. Two weeks ago, Erdogan’s Justice and Development Party, known by its Turkish initials AKP, had rejected calls for a parliamentary investigation of safety practices in the Soma mines.

“The government’s response has been absolutely inadequate,” said Union of Mine Workers President Tayfun Gorgun, reached by phone in Soma. “The conditions in the mine were worse than they should have been. The workers were forced to work long hours to make their bosses more money.”

Angry demonstrations were held for a second day in cities including Istanbul; the capital, Ankara; and the coastal city of Izmir, near Soma. Police fired tear gas and water cannons to try to contain the protests. Demonstrators in Ankara reportedly chanted, “The fires of Soma will burn the AKP.”

On a visit to Soma on Wednesday, Erdogan, under police protection, was heckled by a hostile crowd, and a widely circulated photo showed a man identified as a senior Erdogan aide kicking a prone demonstrator.

The mine tragedy could carry damaging political repercussions for the prime minister, who is thought to be positioning himself for a presidential run in August.

Erdogan has promised a thorough investigation of the accident, but he drew criticism for comments Wednesday in which he cited mine disasters in other countries, some of them more than a century earlier, and said such accidents were “the nature of the work.”

“I went back in British history,” Erdogan said, according to Hurriyet. “Some 204 people died there after a mine collapsed in 1838. In 1866, 361 miners died in Britain. In an explosion in 1894, 290 people died there.” The newspaper pointedly added that the prime minister chose “not to elaborate on how accidents in 19th century Britain might be applicable to Soma’s unfolding disaster.”

President Abdullah Gul, once a close ally of Erdogan, received a far less hostile welcome when he visited the site Thursday.

“I feel the pain of all of you,” he told rescuers and relatives, urging Turks to pull together in the face of a national tragedy.

But the government is likely to face tough scrutiny of its role.

“This was an accident that has been waiting to happen,” said Emma Sinclair-Webb, senior Turkey researcher at Human Rights Watch. “Now the alarm bells are ringing.”