WEST, Texas -- A massive explosion at a fertilizer plant near Waco last night killed an unknown number of people and injured dozens of others, leaving the factory a smoldering ruin and leveling buildings for blocks.

The explosion at West Fertilizer in West, a community about 20 miles north of Waco, happened shortly before 8 p.m. and could be heard as far away as Waxahachie, 45 miles to the north. West Mayor Tommy Muska, also a volunteer firefighter, said the town's department had been fighting a fire at the plant about 6:30 p.m.

Although authorities said it will be some time before they know the full extent of the loss of life, Texas Department of Public Safety spokesman D.L. Wilson said just after midnight that an unknown number of people had died.

Earlier, Glenn A. Robinson, chief executive of Hillcrest Baptist Medical Center in Waco, told CNN that his hospital had received 66 injured, including 38 who were seriously hurt. Neither he nor reps for his hospital and White Hospital in Temple immediately returned messages from the AP. A spokesman at Providence Health Center was not available for comment.

Muska told reporters that his city of about 2,800 residents needs "your prayers." He said main fire at the plant was under control as of 11 p.m., but residents were urged to remain indoors because of the threat of new explosions or leaks of ammonia from the plant's ruins.

advertisement | advertise on newsday

A member of the city council, Al Vanek, said there is a four-block area around the explosion "that is totally decimated."

Among the damaged buildings was what appeared to be a housing complex with a collapsed roof, a middle school and the West Rest Haven Nursing Home, from which first responders evacuated 133 people, some in wheelchairs.

Texas Gov. Rick Perry said Wednesday night that state officials were waiting for details about the severity.

Debby Marak, 58, told The Associated Press she was driving about a block away when the blast occurred. "It was like being in a tornado," she said. "Stuff was flying everywhere. It blew out my windshield."