The Los Angeles Fire Department’s Arson Unit is investigating an incident that occurred early Monday morning where a flammable liquid was ignited at a residence in the 100 block of N. Vista Street.

It was reported by the that the liquid was contained in a Molotov cocktail thrown at the residence, but officials would neither confirm or deny the report.

The incident was reported at 1:20 a.m., according to LAFD spokesperson Erik Scott, and when firefighters arrived, the flames had already been extinguished by someone at the residence. Scott confirmed that a flammable liquid had been ignited at the front of the house, but would not confirm what type of liquid.

Scott said there were no injuries. Michael Camello, an investigator with the LAFD’s Arson Squad, also refused to comment.

“Unfortunately, we can’t give out any information at this time,” Camello said. “This is a criminal investigation, and we will not be putting any information out.”

Lt. Bryan Wong, with the Los Angeles Police Department’s Wilshire Division, also said police were attempting to gather evidence about what happened, but added that he could not comment on the incident pending the LAFD investigation.