NEW VIDEO: Four killed, nine injured in fiery crash in Phoenix

Investigators said a tanker truck filled with milk slammed into several vehicles

(KYMA, KECY, NBC NEWS) - At least four people were killed and nine others were injured in a fiery multivehicle crash in Phoenix, authorities said Wednesday.

The crash, which involved a semitruck transporting milk, occurred about 10 p.m. MT in the eastbound lanes of Loop 202 near Papago Park, the Arizona Department of Public Safety said.

Firefighters who responded to the scene found the semitruck leaking milk and diesel fuel, and a fire inside one of the vehicles involved in the crash, according to NBC affiliate KPNX of Phoenix. Investigators said the truck was going east on the highway, failed to slow down for traffic congestion in the area of 52nd and Van Buren streets and hit seven vehicles.

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The tank separated from the truck, crossed traffic, flipped over a concrete barrier, landed on the westbound lanes and caught fire, the state agency said.

Four people died at the scene and six others, including four men and two women, were taken to the hospital in critical condition, according to the Phoenix Fire Department. Two other men and a 6-year-old girl were stable.

The identities of the victims were not immediately released by authorities.

Investigators said there was no sign of impairment.

Both directions of Loop 202 were shut down for a time. While westbound lanes have reopened, eastbound lanes are expected to be closed throughout the morning.