WASHINGTON (AFP) – Four US miners missing after a deadly blast at a West Virginia coal mine have been found dead, a discovery that brought to a tragic conclusion a nearly week-long search for survivors, local officials announced early Saturday.

"We did not receive the miracle we prayed for," West Virgina Governor Joe Manchin told reporters. "This journey has ended and now the healing will start."

The grim discovery brought the total death toll from Monday's explosion to 29.

The blast at the Upper Big Branch Mine in West Virginia, which is run by Massey Energy, is considered the worst US coal mine accident since 1984.

On Friday, dangerous conditions forced rescuers to suspend their desperate search for the four missing men, but it resumed after the shafts had been ventilated.

President Barack Obama said he had asked the labor secretary and other officials in his administration to report next week on the tragedy "so that we can take the steps necessary to prevent such accidents in the future."

In an emotional account, the president described speaking Wednesday to surviving members of a family that lost three relatives in the mine near the town of Montcoal. Two other members of the same family were in the mine but managed to escape.

One of those who perished, a 25-year-old, had written to his girlfriend and daughter on the morning ahead of the accident that "'if anything happens to me, I'll be looking down from heaven at you all,'" Obama recounted.

He then quoted a psalm from the Bible, saying its words were "particularly poignant right now. Those words read: 'You, O Lord, keep my lamp burning; my God turns my darkness into light.'"

Federal prosecutors have brought two criminal complaints for safety violations at other mines run by Massey Energy, one of the biggest mining concerns in the United States and the largest in Appalachia.

Massey has been hit with dozens of safety violations over the years, including 57 citations in the month of March, and paid out 4.2 million dollars in criminal and civil fines last year.

Still, company officials insist they had an above average safety record.