A massive crash involving more than 130 cars on an icy Texas interstate leaves at least six people dead and dozens injured.

At the crash scene on Interstate 35 near downtown Fort Worth, a tangle of semitrailers, cars, and trucks had smashed into each other.

According to officials, a total of 65 people required medical attention after the crash. First responders rushed at least 36 of the victims to hospitals.

Officials added the crash involved a pileup of 133 cars. Multiple people were trapped in cars, and fire crews had to use hydraulic rescue equipment to rescue them.

The devastating crash occurred shortly after 6 am, February 11, amid a winter storm that dropped freezing rain, sleet, and snow on many parts of the country.

Although the cause is unclear, a shocking before the crash video shows a truck plowing into a barrier after losing control on the icy road.

Afterward, dozens of vehicles traveling behind the truck smashed into each other. The crash site stretched back for 1.5 miles.

First responders described the scene as a 'mass casualty incident.' Crushed vehicles stacked on top of one another, trapping helpless drivers inside.

Officials initially reported the death toll of five people but later confirmed a sixth fatality.

The names of the victims, however, haven't yet been released.

One Medstar official also confirmed no children were among the deceased or seriously injured.

Commenting on the incident, Fort Worth fire spokesman Mike Drivdahl said:

"This is a major catastrophe in our city."

"Our thoughts and prayers are with the [victims and their families]."

Most of the crash victims were health care workers and emergency responders. Many were heading to or from work at the time.

Three Fort Worth police officers en route to work also sustained minor injuries.

Matt Zavadsky, a spokesman for the ambulance service MedStar, explained:

"We did see a large number of people that were victims of this accident, that were in scrubs... That had hospital IDs on."

An investigation into the cause of the crash is underway.

However, local politicians are questioning whether the roads were properly prepared for the adverse weather conditions.

One first responder also told NBC News that the stretch of road 'was solid ice when police and firefighters first arrived' at the scene.

Rescue workers were even slipping on the ice as they attempted to reach victims inside their cars. To mitigate the slippery condition, they had to lay salt and sand over the road.

Meanwhile, one driver at the the crash also remarked on the icy conditions of the road.

He said:

"All of a sudden, there's ice, and everybody's wrecking."

"You don't see the ice, 'til you feel it… You can't stop, so I steered off into that wall… Then the people behind me just bam, bam, bam, bam."

According to the National Weather Service, Fort Worth had been under a winter weather advisory for the last few days.

Across the Dallas-Fort Worth metro area, icy weather also caused accidents the same day. Arlington police said they responded to at least 82 crashes before 9 am.

In Dallas, three people died and another was hospitalized in critical condition in two separate collisions.

The Texas Department of Transportation said its thoughts are with the families of all of those involved in crashes.

It said in a statement:

"[During all winter weather events, it takes] proactive, advance measures such as pretreating its roads, which can help prevent ice from sticking to the roadway."

"Conditions on roadways can change very fast. And unfortunately, even with proactive measures, the unpredictable severe Texas weather can still result in some ice accumulating."