Protesters run away from water canon fired by the riot police during a demonstration blaming the ruling AK Party (AKP) government for the mining disaster in western Turkey, in central Istanbul May 14, 2014. [Photo/Agencies]

SOMA, Turkey -- Amid wails of grief and anger, rescue workers coated in grime trudged repeatedly out of a coal mine Wednesday with stretchers of bodies that swelled the death toll to 274 - the worst such disaster in Turkish history.

Hopes faded for 150 others still trapped deep underground in smoldering tunnels filled with toxic gases.

Anti-government protests broke out in the mining town of Soma, as well as Istanbul and the capital, Ankara, with Prime Minister Recep Tayyip Erdogan heckled as he tried to show concern. Protesters shouted "Murderer!" and "Thief!" and Erdogan was forced to seek refuge in a supermarket, surrounded by police.

Tensions were high as hundreds of relatives and miners jostled outside the mine's entrance Wednesday, waiting for news amid a heavy police presence. Rows of women wailed uncontrollably and men knelt sobbing or simply stared in disbelief as rescue workers removed body after body, some charred beyond recognition.

Energy Minister Taner Yildiz said 787 people were inside the coal mine at the time of Tuesday's explosion: 274 died and 363 were rescued, including scores who were injured.

The death toll topped a 1992 gas explosion that killed 263 workers near Turkey's Black Sea port of Zonguldak. It also left 150 miners still unaccounted for.

Erdogan declared three days of national mourning and postponed a trip to Albania to visit the mine in Soma, 155 miles (250 kilometers) south of Istanbul. He warned that some radical groups would try to use the disaster to discredit his government.

"These are ordinary things. There is a thing in literature called `work accident'... It happens in other work places, too," Erdogan said. "It happened here. It's in its nature. It's not possible for there to be no accidents in mines. Of course we were deeply pained by the extent here."

In this industrial town, where coal mining has been the main industry for decades, Erdogan's ties to mining leaders were vehemently noted. Townspeople said the wife of the Soma mine's boss works for Erdogan's party and the boss himself had skipped town.

In Istanbul, hundreds of demonstrators gathered outside the headquarters of mine owner Soma Komur Isletmeleri A.S. Police used tear gas and water cannon to break up a group who tried to march to the city's iconic Taksim Square to denounce poor safety conditions.

Police also dispersed a group marching to the energy ministry in Ankara to protest the deaths.

Authorities said the disaster followed an explosion and fire at a power distribution unit and most deaths were caused by carbon monoxide poisoning. Erdogan promised the tragedy would be investigated to its "smallest detail" and that "no negligence will be ignored."

Mining accidents are common in Turkey, which is plagued by poor safety conditions. Tuesday's explosion tore through the mine as workers were preparing for a shift change, which likely raised the casualty toll.

Turkey's Labor and Social Security Ministry said the mine had been inspected five times since 2012, most recently in March, and that no safety violations were detected. But the country's main opposition party said Erdogan's ruling party had recently voted down a proposal to hold a parliamentary inquiry into a series of small-scale accidents at the mines around Soma.

Turkish mine explosion death toll tops 200	22 miners trapped in Yunnan coal mine flood