San Juan de Sabinas, Mexico ? Mexican crews tunneled feverishly Monday through dirt and rock to reach 65 coal miners trapped by a gas explosion 600 feet underground. Relatives grew increasingly desperate after nightfall with no word of their loved ones.

Some of the miners’ family members, who had been camped outside the pit for more than 36 hours, called through a megaphone for more information.

“Tell us the truth!” one man shouted.

Officials said that while prospects were dim, there was still a chance of finding survivors from Sunday morning’s explosion at the Pasta de Conchos mine near the town of San Juan de Sabinas, 85 miles southwest of Eagle Pass, Texas.

The trapped men had carried only six hours of oxygen, 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 precious oxygen was arriving to where the miners were trapped.

Some relatives prayed with priests and pastors who joined them at the pit entrance.

Women wept openly and swayed with their arms in the air as the religious leaders spoke, and men wiped tears from their eyes.

“We are waiting for a miracle from God,” said Norma Vitela, whose trapped husband, Jose Angel Guzman, had previously told her of problems with gas in the mine. She said the father of four, who earns $75 a week, could not afford to quit.

Juan Rebolledo, vice president of international affairs for mine owner Grupo Mexico, said oxygen tanks were scattered throughout the site, but it was impossible to know whether the trapped miners had access to any of them.

Beatriz Gallegos waits for news of her husband, one of the 65 trapped coal miners, in San Juan de Sabinas, Mexico, Monday, Feb. 20, 2006. Rescue workers using picks, shovels and their hands tunneled feverishly through dirt, wood, metal and rock in an attempt to reach the miners, who were trapped by a gas explosion 600 feet underground early Sunday.

More than 35 hours of digging had pushed rescue teams 400 yards into the mine, about 100 yards from where two conveyor belt operators were believed to be trapped, said Sergio Robles, director of emergency services for Coahuila state.

But others were thought to be trapped as far as one to three miles from the mine’s entrance.

Robles said rescuers avoided using electric or gas-powered machinery because of the presence of explosive gases. Medical doctors were on the site to examine rescue workers as they emerged from their eight-hour shifts in the tunnels.

Asked whether he believed there were more survivors, Robles said: “It would be difficult because of the presence of gas. But we are holding out hope of finding someone alive.”

Robles said the roof of the mine was better reinforced after 400 meters, giving rescuers hope that they might be able to advance more quickly. He said if there were survivors, they could very well be trying to dig their way out from the other side.