Rescuers are still searching for survivors in the rubble of homes destroyed by a fertilizer plant explosion in the rural Texas town of West.
The mayor of the town has said the blast killed 12 people. Among the dead are four paramedics killed in the chemical blast at West Fertilizer Company on Wednesday evening after emergency responders rushed to put out a fire at the plant, West Mayor Tommy Muska said.
He said five volunteer firefighters are listed as missing and feared dead. The cause of the explosion, which injured around 200 people, was not known and officials said no evidence of foul play had been found.
Police initially put the death toll at up to 15, but later on Thursday Texas Department of Public Safety spokesman Jason Reyes told reporters that while the explosion had been deadly, it is not yet known exactly how many had been killed.
The Texas blast happened within days of the deadly Boston marathon bombings and the discovery of poisonous packages sent to President Barack Obama and a Republican senator.
Agents with the US Chemical Safety Board, a federal agency that investigates industrial chemical accidents, and the Bureau of Alcohol, Tobacco, Firearms and Explosives are on the scene of the blast, which was the strength of a magnitude 2.1 earthquake, according to the US Geological Survey.
Firefighters had been battling a fire at the plant on Wednesday night for about 20 minutes before the blast rocked the town of 2,700 people about 32 km north of Waco.
Texas Attorney General Greg Abbott toured the devastated area on Thursday and compared the scene to "a bombing site, the kind you see in Baghdad." He said authorities were combing the area "inch by inch."
The blast destroyed 60 to 80 houses, reduced a 50-unit apartment complex to what one local official called "a skeleton standing up" and left a horrific landscape of burned-out buildings and blackened rubble.