The White House on Wednesday promised a full investigation of the West Virginia coal mine disaster that killed 12 people, and President Bush said the entire nation mourns the loss.

"We send our prayers and heartfelt condolences to the loved ones whose hearts are broken," Bush said at the Pentagon, where he was briefed on Iraq and the war on terror. "We ask that the good Lord comfort them in their time of need."

The president praised West Virginia Gov. Joe Manchin "for showing such compassion" during the crisis and thanked rescuers "who risked their lives to save those miners for showing such courage."

"May God bless the good people of West Virginia," Bush said.

Earlier, his spokesman defended the administration's record on mine safety rules, saying increased safety has been a priority for the Bush administration.

"In fact this administration proposed a fourfold increase in fines and penalties for violations of the Mine Safety and Health Administration rules," White House press secretary Scott McClellan said.

Labor Secretary Elaine L. Chao said the Mine Safety and Health Administration was launching a full investigation to "determine the cause of this tragedy and will take the necessary steps to ensure that this never happens again."

Acting Assistant Secretary David Dye, who heads the Mine Safety and Health Administration, said the investigation will "evaluate all aspects of the accident and response, including compliance with all federal health and safety standards, and how emergency information was relayed about the trapped miners' conditions."

The emotional impact of the loss on the families of the lost miners was intensified when they were told shortly before midnight Tuesday that 11 or 12 trapped miners had been found alive, only to learn three hours later that 12 were dead.

The misinformation was blamed initially on confusion from overhead cell telephone calls that was relayed to anxious family members waiting in a church near the mine.