SAN JUAN DE SABINAS, Mexico — Relatives of 65 Mexican coal miners trapped underground for almost two days by a gas explosion grew increasingly desperate as hopes dimmed that any survivors would be found.

Rescue crews worked through the night, tunneling feverishly through dirt and rock. Officials said that while there was still a chance of finding survivors from Sunday's explosion at the Pasta de Conchos mine, prospects were slim.

Miners' family members, who had been camped outside the mine for nearly two days, called for rescue workers to give them more information.

"Tell us the truth!" a man shouted through a megaphone.

Jesus de Leon, 50, whose 35-year old son is trapped underground, said the wait was unbearable. "If the rescue workers have advanced just one more meter we need to know about it," De Leon said. "They don't tell us anything."

The trapped men had carried only six hours of oxygen when the explosion occurred about 600 feet underground, but officials said they believed a ventilation system that uses huge fans to pump in fresh air and suck out dangerous gases was still working.

Even so, they could not be certain the oxygen was arriving to where the miners were trapped.