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12:12AM EDT: (Reuters) Hundreds of people were likely injured in a fiery explosion on Wednesday night at a fertilizer plant near Waco, Texas, that damaged or destroyed numerous buildings including a school and nursing home, authorities said.

The blast was reported at about 8 p.m. CDT (0100 GMT on Thursday) in West, a town of some 2,700 people about 80 miles (130 km) south of Dallas and 20 miles (32 km) north of Waco.

“It’s a lot of devastation. I’ve never seen anything like this,” said McLennan County Sheriff Parnell McNamara. “It looks like a war zone with all the debris.”

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There was no immediate official word on what sparked the explosion as emergency personnel assisted victims and doused the flames.

A spokesman for the Texas Department of Public Safety, D.L. Wilson, told Reuters the blast had probably caused “hundreds of casualties” and damaged many homes. He added that a nearby nursing home had collapsed from the explosion and that people were believed trapped inside.

McNamara said the nursing home and much of the center of town had been evacuated, and that residences near the explosion had been leveled.

The air in town remained thick with smoke more than two hours after the explosion, and the area around the blast site was littered with shards of wood, bricks and glass.

A Reuters reporter observed that a nearby middle school and several homes were severely burned. Dallas television station WFAA reported from helicopters that roughly a three-block area of West appeared to have been destroyed.

More than 100 people were being taken to Hillcrest Baptist Medical Center in Waco, said vice president of hospital operations David Argueta.

Hillcrest CEO Glenn Robinson told CNN that the hospital was seeing “everything from orthopedic injuries to patients that are experiencing serious blood loss.”

Governor Rick Perry issued a statement saying his office had “mobilized state resources to help local authorities” deal with the incident.

A White House official said the Obama administration was aware of the situation and monitoring local and state response through the Federal Emergency Management Agency.

The explosion came two days before the 20th anniversary of a fire in Waco that engulfed a compound inhabited by David Koresh and his followers in the Branch Davidian sect, ending a siege by federal agents.

Some 82 members of the sect and four federal agents died at Waco.

11:44PM EST: Governor Rick Perry issued a statement saying his office had “mobilized state resources to help local authorities” deal with the incident.

AUDIO: Scanner from first 5 minutes after explosion:

11:40PM EDT: ABC News can confirm from DPS Spokesperson Gail Scarborough that 75-100 houses and business were completely destroyed in and around the plant. There are at least 200 people injured with at least 40 critical injuries.

VIDEO: [A dad records video of the fertilizer plant on fire. Then it explodes…]

Click HERE to watch this video on a mobile device.

Several fires continued to burn in West two hours after the blast. In aerial footage, dozens of emergency vehicles could be seen amassed at the scene. Entry into West was slow-going, as the roads were jammed with emergency vehicles rushing in to help out.

Authorities set up a staging area on the local high school’s football field, which was lit up with floodlights. Ambulances and several dozen injured people could be seen being taken away or seated in wheelchairs as they are treated and await transport.

Department of Public Safety troopers were using their squad cars to transport those injured by the blast and fire at the plant in West, a community north of Waco, Gayle Scarbrough, a spokeswoman for the department’s Waco office, told television station KWTX. She said six helicopters were also en route to help out.

The explosion at West Fertilizer was reported shortly before 8 p.m. in a frantic call from the scene, KWTX reported.

A West Fire Department dispatcher told The Associated Press that any casualties would be transported to hospitals in Waco, which is about 90 miles north of Austin.

The explosion knocked out power to many area customers and could be heard and felt for miles around.

Brad Smith, who lives 45 miles north of West in Waxahachie, told the station that he and his wife heard what sounded like a thunderclap.

11:18PM EDT: (AP) An explosion Wednesday night at a fertilizer plant near Waco sent flames shooting high into the night sky, leaving the factory a smoldering ruin, causing major damage at nearby buildings and injuring numerous people.

The blast at the plant in West, a community north of Waco, happened shortly before 8 p.m. and could be heard as far away as Waxahachie, 45 miles to the north.

Several fires continued to burn in West two hours after the blast. In aerial footage from Dallas’ NBC affiliate, WDFW, dozens of emergency vehicles could be seen amassed at the scene. Entry into West was slow-going, as the roads were jammed with emergency vehicles rushing in to help out.

Authorities set up a staging area on the local high school’s football field, which was lit up with floodlights. Ambulances and several dozen injured people could be seen being taken away or seated in wheelchairs as they are treated and await transport.

Department of Public Safety troopers were using their squad cars to transport those injured by the blast and fire at the plant in West, a community north of Waco, Gayle Scarbrough, a spokeswoman for the department’s Waco office, told television station KWTX. She said six helicopters were also en route to help out.

The explosion at West Fertilizer was reported shortly before 8 p.m. in a frantic call from the scene, KWTX reported.

A West Fire Department dispatcher told The Associated Press that any casualties would be transported to hospitals in Waco, which is about 90 miles north of Austin.

The explosion knocked out power to many area customers and could be heard and felt for miles around.

Brad Smith, who lives 45 miles north of West in Waxahachie, told the station that he and his wife heard what sounded like a thunderclap.

Lydia Zimmerman, told KWTX that she, her husband and daughter were in their garden in Bynum, 13 miles from West, when they heard multiple blasts.

“It sounded like three bombs going off very close to us,” she said.

11:00PM EDT: Hundreds of people were likely injured in a fiery explosion on Wednesday night at a fertilizer plant near Waco, Texas, that damaged or destroyed numerous buildings, including a nursing home, authorities said.

The blast was reported at about 8 p.m. CDT (0100 GMT on Thursday) in West, a town of some 2,700 people about 80 miles (129 km) south of Dallas and 20 miles (32 km) north of Waco.

A spokesman for the Texas Department of Public Safety, D.L. Wilson, told Reuters the blast had resulted in “probably hundreds of casualties,” saying he did not know if any of those were fatalities.

He added that a nearby nursing home collapsed from the explosion and that people were believed to be trapped inside.

9:50PM EDT: Authorities in Texas reported a large explosion on Wednesday at a fertilizer plant in the town of West, near Waco.

The blast, reported shortly before 8 p.m. central time, was confirmed by Waco police dispatch operators. It was felt as far away as 65 miles.

Fire dispatchers were reporting dozens of people trapped, with numerous structures on fire.

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