HOLMES MILL, Ky. - An explosion in an eastern Kentucky coal mine killed five miners Saturday, Gov. Ernie Fletcher said. A sixth miner was able to walk away from the blast and out of the mine on his own.

The blast at the Darby Mine No. 1 in Harlan County occurred between midnight and 1 a.m. EDT while a maintenance shift was on duty, said Amy Louviere, a spokeswoman for the U.S. Mine Safety and Health Administration. It was the latest in a string of mine accidents to hit U.S. coal country this year.

"We don't know the details of the cause," Fletcher told The Associated Press.

The five dead miners were found by rescue workers, the governor said. The rescue teams initially found three dead workers and later found two more, he said.

Authorities identified the victims as Amon Brock, Jimmy Lee, Roy Middleton, George William Petra and Paris Thomas Jr., but their ages and hometowns were not immediately available.

The survivor, identified as Paul Ledford, was taken to Lonesome Pine Hospital in Big Stone Gap, Va., where he was treated and released, hospital spokeswoman Amy Stevens said.

Fletcher said Ledford was closer to the mine's exit than his co-workers.

It was not clear how many workers were on duty when the blast occurred, but Louviere said no production was going on at the time.

The underground mine, operated by Kentucky Darby LLC, is located about 250 miles southeast of Louisville in a mountainous area near the Virginia border. A man who answered the phone at a Kentucky Darby office declined to comment Saturday, saying the company was too busy.

Relatives of the miners gathered before dawn at the Cloverfork Missionary Baptist Church near the mine to await word about their loved ones. State and federal mine officials informed the family members of the deaths, said Mike Blair, the church's pastor.

"There's just a lot of heartbroken people," he said.

Local magistrate Chad Brock said the deaths would touch many lives.

"There's not going to be a family that's not affected in some way," he said. "You either know them or you're kin to them."

Harlan County Judge-Executive Joe Grieshop said the accident "shakes up our county because coal mining is a way of life for our people."

United Mine Workers President Cecil Roberts urged state and federal mine officials to "redouble their inspection and enforcement activities, starting now."

"This tragedy only compounds what has already been a horrific year in America's coal mines," Roberts said in a statement.

Mine safety issues have been a key concern of lawmakers ever since two accidents in January killed 14 West Virginia coal miners.

Earlier this week, a key Senate committee endorsed a bill to make coal mining safer. The legislation would require miners to have at least two hours of oxygen available instead of one and would require mine operators to store extra oxygen packs along escape routes.

The bill also would require mines to have two-way wireless communications and tracking systems in place within three years. It now goes to the full Senate.

Sen. Edward Kennedy (news, bio, voting record), D-Mass., a key architect of the bill, said the explosion "underscores the need for swift action to improve the safety of our nation's coal mines."

The Mine Safety and Health Administration recently issued a temporary rule requiring coal operators to give miners extra oxygen, but miners have been pressing Congress for a permanent fix.

In the Jan. 2 Sago mine explosion in West Virginia, one man was killed in the blast and 11 others died from carbon monoxide poisoning. Randal McCloy Jr., the only miner who survived, has said at least four of the miners' air packs did not work, forcing the men to share.

The federal Mine Safety and Health Administration said that the five deaths Saturday raised the national death toll from coal mining accidents to 31 this year, with 10 of the deaths in Kentucky.