The death toll in Turkey's horrific coal mine accident rose to 238 Wednesday with hundreds of miners still trapped underground.
Prime Minister Recep Tayyip Erdogan reached the site of the accident in the western province of Manisa, 250 km south of Istanbul, Xinhua reported.
Energy Minister Taner Yildiz said most of the victims died of carbon monoxide poisoning following a fire and explosion at the mine in Soma district.
The disaster occurred in the privately-owned mine during a shift changeover Tuesday. The fire broke out 150 metres underground.
He said the accident could become "the worst disaster" in Turkish history since hundreds more remained trapped underground.
President Abdullah Gul cancelled an official visit to China, scheduled for May 15-21, because of the disaster. Erdogan also called off a trip to Albania.
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Yildiz said 363 of the 787 miners who were working underground at the time of accident have been accounted for, including the deceased.
Rescue efforts were continuing but hopes of finding more survivors were diminishing.
The accident has sparked widespread anger as many denounced poor safety measures, accusing the government and mine companies of negligence.
Anti-government protests were staged in Istanbul, Ankara, Izmir, Antalya and other cities over the tragedy, with protesters demanding the resignation of the ruling Justice and Development Party.
More than 500 people gathered in front of the Soma Holding headquarters in Istanbul Wednesday.
In capital Ankara, riot police fired tear gas and water cannon at hundreds of university students who tried to march to the energy ministry.
The workers' unions called for a nationwide general strike Thursday.
Also Wednesday, a coal mine operating without license collapsed in Gelik village in northern Turkey, trapping the owner underground, according to Dogan news agency.
Mining accidents kill dozens of miners each year in Turkey.
The last major mining tragedy in Turkey occurred in 1992 when a fire and explosion killed 263 people. Two other mining accidents took place in 1983 and 1990, leaving 103 and 68 dead respectively.
Turkey has declared three days of national mourning for those killed, the prime minister's office said.