Victor Kotsev

Special for USA TODAY

ISTANBUL — Protests erupted across the country and angry relatives of the nearly 300 victims of a mine disaster booed Prime Minister Recep Tayyip Erdogan when he visited the mine and told them that mine accidents are "usual things."

In the capital Ankara, police used tear gas and water cannon to disperse a group of students who tried to march on the Energy Ministry in protest of poor mine safety. Protests also broke out in front of the offices of the mining company, Soma Holding, in Soma and near Taksim Square in Istanbul – the center of anti-government protests last year.

"I am angry and confused. This is such a horrible tragedy," said Ekim Hakan, a student. "But I feel helpless. The government should be held accountable for this, but they are not listening to us."

At least 274 miners died in a coal mine explosion and fire Tuesday in Soma. The mining company said 450 other miners were rescued, but the fate of about 150 others miners remained unclear in one of the world's deadliest mining disasters in decades.

Hundreds of relatives and miners jostled outside the coal mine in western Turkey, waiting for news amid a heavy police presence. Rows of women wailed, men knelt sobbing and others stared in disbelief as rescue workers removed a steady stream of bodies throughout the night and early morning.

Many in the crowd expressed anger at Erdogan's government, shouting that Erdogan was a "murderer!" and a "thief!"

Erdogan said some radical groups would try to use the disaster to discredit the government over the disaster.

"Our hope is that, God willing, they will be brought out," he said of those still trapped. "That is what we are waiting for."

In downtown Soma, protesters confronted riot police Wednesday afternoon in front of the ruling NKP party headquarters. Police had gas masks and water cannons. Police set up fences and stood guard around Soma state hospital to keep the crowds away from scores of injured miners.

"The government rejected an opposition motion to investigate safety at the mine a couple of weeks ago, so they have some explaining to do, to say the least," said William Hale, a professor emeritus of Turkish at the School of Oriental and African Studies in London who lives in Istanbul.

"The private company which took over the previously state-owned mine two years ago will come under severe scrutiny. If the government engages in a cover-up, this will be very damaging for them," he said.

Hopes were fading, officials said, as rescuers raced Wednesday to reach miners trapped deep underground in the coal mine.

Energy Minister Taner Yildiz said 787 people were inside the coal mine in Soma, about 155 miles south of Istanbul, at the time of the explosion Tuesday.

"Regarding the rescue operation, I can say that our hopes are diminishing," Yildiz said.

He said 57 mine workers were injured and that most of the deaths were from carbon monoxide poisoning after a fire was triggered by an electrical fault. He said the fire was still blazing inside the mine hours after the blast.

The blast happened during a change in shifts.

Mining accidents are common in Turkey, where safety conditions are sometimes poor. In 1992, a gas explosion killed 263 mine workers near the Black Sea port of Zonguldak.

SOMA Komur Isletmeleri A.S., which owns the mine, said the accident occurred despite the "highest safety measures and constant controls" and that an investigation was being launched.

"Our main priority is to get our workers out so that they may be reunited with their loved ones," the company said in a statement.

Andrew Watson, of Mines Rescue Service, a health and safety training company based in the U.K., said it appeared that the mine was not properly vented of flammable gasses and ignited.

"The one thing we can say is that for decades now the means of controlling that environment in terms of the technology has been available," added Watson. "When the methane reached a certain point, the power should have automatically cut off. So that was either not in place here or it has not been managed properly."

Analysts said the safety standards in the mine were low.

"Turkish coal isn't very high quality — it is a brown coal variant called lignite — and thus, doesn't generate much value," said Hamid Akin Unver, an assistant professor of international relations at Kadir Has University in Istanbul. Unver said the Soma mining facility's operating company may have adopted low standards of safety.

The Turkish government, which has been rocked by recent allegations of corruption and mass protests, is likely to take another hit over the accident:

According to a report in Turkish daily Hurriyet, the private company that operates the mine had recently drastically cut production costs from $130 a ton to $24 a ton by using domestically produced electric transformers and non-unionized subcontractors.

Turkey's Labor and Social Security Ministry said in a statement that the mine had undergone five inspections since 2012, the last one in March 2014, and no problems had been reported.

Contributing: Kim Hjelmgaard from London; Associated Press