SOMA, Turkey -- Sensors noted high levels of toxic gas inside a coal mine days before the disaster that killed 301 workers in Turkey but company officials took no action, Turkish news reports said Monday.
Prosecutors, meanwhile, formally arrested two more people for the devastating mine fire in the western town of Soma, raising the number of suspects facing charges of negligent death to five. Those detained included executives and supervisors at mine owner Soma Komur Isletmeleri A.S., prosecutors say.
Chief prosecutor Bekir Sahiner said 25 people were initially detained as part of the probe, but several were released without charges while eight others were released but could be charged later. Authorities were still questioning others, including the company's CEO, Can Gurkan, the state-run Anadolu Agency reported.
The Hurriyet, HaberTurk and other Turkish newspapers said prosecutors and inspectors probing the worst mining disaster in Turkey's history had seized data from the mine that indicated sensors showed high gas levels inside the mine as early as two days before the May 13 disaster. The reports say company officials did not record these high levels on log books and took no precautionary actions.
The Turkish newspapers did not cite source for their reports. Sahiner did not answer calls and no one picked up telephones at the prosecutors' office in Soma or in the nearby city of Akhisar, which is leading the probe.
But miners who survived the disaster also told The Associated Press that supervisors ignored rising gas levels and failed to take precautionary measures. They have accused the company of failing to heed safety concerns and that government inspections has been superficial.
Sahiner said Saturday that a preliminary probe indicated that coal had been smoldering days before the disaster, causing the roof to collapse in one part of the mine and unleashing toxic gases that spread throughout.
Government and mining officials have both said that most victims died from toxic gases released by the fire. They have insisted, however, that the mine was inspected regularly, that safety standards were high and that negligence wasn't a factor in the fire.
Government officials have promised to investigate and pledged that any mine officials found to be negligent would be punished. Still the disaster has provoked anger at a critical time for Prime Minister Recep Tayyip Erdogan, as he mulls running in August's presidential election.
Police have broken up protests denouncing poor mine safety in Soma and in Turkey's three largest cities of Istanbul, Ankara and Izmir.
Nearly 2,000 university students, some wearing hard-hats, called on the government to resign as they marched Monday in Ankara to commemorate the beginning of the Turkish War of Independence started on May 19, 1919.
Erdogan on Monday defended the government's response to the disaster and rejected accusations that the mining company had political ties to his ruling party.
"They say the boss is a party supporter," Erdogan said. "I saw him for the first time (in Soma). I don't know him... They (opponents) think they will gain from such slander."
Turkey's national soccer team visited Soma on Monday in a show of solidarity and prayed at the miners' graves.