Energy Minister Taner Yildiz said 787 people were inside the coal mine in Soma at the time of Tuesday's explosion and 363 of them had been rescued. Scores were injured, Yildiz told reporters in Soma, where he was overseeing operations by more than 400 rescuers.
The last worker rescued alive emerged from the mine around dawn, a government official said on condition of anonymity because she didn't have prior authorization to speak publicly to journalists about the issue. As of 3:30 p.m., it had been about 10 hours since anyone had been brought out alive.
"Regarding the rescue operation, I can say that our hopes are diminishing," Yildiz said before Erdogan's visit.
Erdogan said there were an estimated 120 workers still inside the mine.
"Our hope is that, God willing, they will be brought out," he said. "That is what we are waiting for."
Tensions were high as hundreds of relatives and miners stood outside the mine. The crowd shouted at officials, including when Yildiz passed by, and some wailed each time a body was brought up. A heavy police presence was in place around the mine.
The explosion tore through the mine as workers were preparing for a shift change, officials said, which likely raised the casualty toll because there were more miners inside than usual.
Mining accidents are common in Turkey, which is plagued by poor safety conditions. Turkey's worst mining disaster was a 1992 gas explosion that killed 263 workers near the Black Sea port of Zonguldak.
In Istanbul, hundreds of demonstrators gathered outside the headquarters of the company which owns the mine, Soma Holding. In the capital, Ankara, police dispersed a group who tried to march to the energy ministry to protest the deaths, the Dogan news agency reported.
Erdogan warned that some radical groups would try to use the disaster to discredit the government.
Turkey's Labor and Social Security Ministry said the mine had been inspected five times since 2012, including in March of 2014, and that no issues violating work safety and security were detected. The country's main opposition party said Erdogan's ruling party had recently voted down a proposal for the establishment of a parliamentary inquiry into a series of small-scale accidents at mines around Soma.
Rescue workers emerged at a slow pace from the mine with stretchers carrying bodies, which were covered in blankets. The corpses' faces were blackened like the coal.
One man, who declined to be named, said he had led a 10-man team about a kilometer (half-mile), or halfway, down the mine into the tunnels and had recovered three bodies.
But the men had to flee because of smoke from coal that had been lit by the explosion, he said. Another man walked down the stairs from the mine's entrance weeping, with a look of dejection. Behind him, two groups bearing heavy stretchers pushed through the crowd like caterpillars.
As bodies were brought out on stretchers, rescue workers pulled blankets back from the faces of the dead to give jostling crowds of anxious family members a chance to identify victims. One elderly man wearing a prayer cap wailed after he recognized one of the dead, and police restrained him from climbing into an ambulance with the body.
An injured rescue worker who emerged alive was whisked away on a stretcher to the cheers of onlookers. Yildiz said rescue operations were hindered because the mine hadn't been cleared of gas.
Authorities say the disaster followed an explosion and fire caused by a power distribution unit.
Yildiz said earlier that some of the workers were 420 meters (460 yards) deep inside the mine. News reports said the workers couldn't use elevators to escape because the explosion had cut off power.
Overnight, people cheered and applauded as some trapped workers emerged. But others were consumed by grief.
Emine Gulsen, part of a group of women who sat wailing near the entrance to the mine, chanted, "My son is gone, my Mehmet." Her son, Mehmet Gulsen, 31, has been working in the mine for five years.
Mehmet Gulsen's aunt, Makbule Dag, held out hope. "Inshallah" (God willing), she said.
Police set up fences and stood guard around Soma state hospital to keep the crowds away.
SOMA Komur Isletmeleri A.S., which owns the mine, said the accident occurred despite the "highest safety measures and constant controls" and added 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.
Suzan Fraser reported from Ankara, Turkey. Berza Simsek in Soma contributed to this report.