Casualties in a massive explosion that rocked a fertilizer plant in central Texas on Wednesday are estimated at hundreds of people, US media reported, according to RIA Novosti.

The blast tore through the West Fertilizer plant in the town of West at about 08.00 pm local time shortly after firefighters arrived at the facility to fight a fire, according to reports citing local officials.

The explosion reportedly damaged dozens of buildings in the surrounding area, including a school and a nursing home with over 130 residents.

There has been no official confirmation yet of the numbers of people injured or any fatalities, but images posted by US media show numerous emergency vehicles at the site and medical personnel tending to groups of under the floodlights.

“We are monitoring developments and gathering information as details continue to emerge about this incident,” Texas Gov. Rick Perry said in a statement late Wednesday. “We have also mobilized state resources to help local authorities.”