An explosion rocked Los Angeles on Wednesday, injuring at least 17 people -- including nine LAPD officers -- after a bomb squad attempted to detonate improvised explosive devices that were seized at a home along with a cache of illegal fireworks.

In a news conference late Wednesday, Los Angeles Police Department Chief Michel Moore said authorities responded to the home, where they found thousands of pounds of illegal fireworks, as well as improvised explosive devices, described as "more unstable." A suspect was arrested in connection to the items seized at the home, police said. 

The LAPD bomb squad transferred the improvised devices into a containment vehicle, and detonated them, believing it would contain the blast, which overturned a car and shattered windows in the neighborhood, Moore said, according to the Los Angeles Times

CALIFORNIA HS HAS CHAMPIONSHIP REVOKED OVER TORTILLA THROWING INCIDENT

"Clearly protocols were followed and pursued, but something happened in that containment vehicle that should have not happened and we don’t know why," he added. "We intend to find out why."

A cache of illegal fireworks seized at a South Los Angeles home exploded unexpectedly Wednesday. (FOX 11)

Earlier, the LAPD tweeted that bomb squad officers were in the process of seizing over 5,000 pounds of illegal fireworks in the area at the time of the blast. "Some of the fireworks were being stored in our Bomb Squad trailer as a precautionary measure," the LAPD wrote. 

Of the 17 people injured, 16 were taken to the hospital – with one declining transport, according to the Los Angeles Fire Department. The LAFD wrote that nine LAPD officers and one Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) agent sustained minor injuries. At least seven people were also hurt, including three who had moderate injuries. 

The department added that several homes and a building were impacted by the blast.

"There are PIOs at scene and this is an ongoing situation in which the area will be impacted for hours due to evacuations, rendering the location safe, and investigation," the LAPD noted. "Updates will be provided as they become available."

FAMILIES STOCK UP ON FIREWORKS FOR JULY 4 AMID SUPPLY SHORTAGE

FOX 11 of Los Angeles reported that investigators and bomb squad officials responded to the home earlier in the day after receiving a tip from a community member. A forklift was seen carrying dozens of boxes out of the house, images showed. 

The suspect, identified as Arturo Cejas III, was arrested on suspicion of possessing fireworks and destructive devices, as well as suspicion of child endangerment – because two children were found at the home, police said, according to Los Angeles's KABC-TV

The explosion in Los Angeles comes just days before the Fourth of July weekend.

On Wednesday, the city hosted its first fireworks buyback program aimed at reducing illegal fireworks during the upcoming weekend, FOX 11 reported. 

"The LAPD supports this event and asks people to be safe, help prevent fires during a dry & bad fire season," the department tweeted on Tuesday evening. "Let's please be considerate of our neighbors, veterans with PTSD, and pets. Turn in your illegal fireworks & receive a free gift."

CLICK HERE TO GET THE FOX NEWS APP

Los Angeles Mayor Eric Garcetti said he directed the LAPD to conduct a full investigation into the incident.

"Illegal fireworks pose a great danger and can cost lives," he said in a statement. "We will prosecute those who use or possess them to the fullest extent of the law."