JUST IN: Many Dead As, Over 15 Cars Destroyed In Ghastly Accident

Multiple people died and at least 10 others were injured in a fiery crash on a Colorado highway that involved at least 15 cars and semi trucks.

Officials did not specify the number of people killed, but said there were "multiple fatalities" in the Thursday crash and subsequent fire on Interstate 70 in Lakewood, Colorado, about 8 miles west of Denver. One firefighter was among the people taken to a local hospital when debris, possibly a tire, exploded.

The accident occurred at around 4:30 p.m. when a semitrailer slammed into several stopped cars at a high rate of speed during a traffic jam, police said. The driver of that semi survived.

"I-70 eastbound traffic was at a standstill or close to a standstill because of a crash way up ahead. … The semi was eastbound and ended up colliding with the stopped cars," Lakewood Police Department agent Ty Countryman said Thursday night. "We're almost four or five hours into this and our crash investigation has really yet to begin -- given the magnitude of the size of this crash."

Authorities avoided giving firm numbers at a press conference on Thursday evening because rescue workers were still working to put out hot spots on the scene.

"The back of my truck lifted up and shoved me forward, and I was hitting other cars," Brian Dickey, who was caught up in the accident, told Denver ABC affiliate KMGH. "When I came to a stop I look in my rearview mirror and all I saw was a bunch of flames. And I jumped out of the vehicle as fast as I could. There was so much fire at the time that I couldn't even really approach any of the other vehicles to see if there was any other survivors or what."

Countryman said the accident could end up being one of the worst in the city's history.

"This is looking to be one of the worst accidents we've had here in Lakewood," Countryman said.

Authorities said at least 12 cars and three tractor trailers were involved, but Countryman said those figures could change by Friday morning as investigators start "pulling things apart."

"It's very hard to tell, given the fire that happened when the crash took place," Countryman said. "It is true carnage there as far as the debris, what's left of cars and trucks, along with the cargoes that were in the semis and things like that."