SOMA, Turkey — As hopes began to fade for hundreds of coal miners still trapped underground in a hellish explosion, antigovernment protests broke out across the country on Wednesday while victims’ families demanded answers in what is emerging as perhaps the worst industrial accident in the country’s history.

Thousands of people have gathered here in Soma, the nearest town to the mine, in hopes of getting news of relatives and friends who are unaccounted for. Their frustrations erupted in a rock-throwing protest in front of the headquarters of the Justice and Development Party of Prime Minister Recep Tayyip Erdogan that was broken up by the police in clouds of tear gas. Demonstrations also broke out in Ankara, the capital, and in Istanbul.

Many relatives of the miners have complained about a lack of information from the government and local emergency agencies. “No official came here to talk to us, explain what’s going on,” said the aunt of a 25-year-old miner.

Near the mine entrance, mournful family members watched mostly in silence as rescue workers slowly removed bodies, some of them charred, from the mine’s fiery and poisonous depths. As the rescue operation dragged on, the official death toll rose to 274.