At least three men were killed and nine other people were injured in a shooting at a Halloween house party in Long Beach Tuesday night and police were searching for the shooters, police said.

The shooting took place at 10:44 p.m. in the 2700 block of Seventh Street, officials said.

Three victims were confirmed dead at the scene and nine others suffered gunshot wounds, some considered life-threatening, police said.

"The crime scene is horrific; there's blood everywhere," Long Beach Police Chief Robert Luna told reporters at a briefing Wednesday morning. "The shooter or shooters fired from an alley behind the residence. Then the shooter or shooters fled in a dark-colored vehicle."

Luna said the three deceased victims were men and the wounded included seven women and two males. There was no update on their conditions, he said.

"Last thing I heard was shots. It was 20 or 30 shots," said a resident, who only gave his first name, Martin.

At 10:44 pm, @lbfirefighters responded to shooting at a residence on the 2700 block of 7th Street. An MCI was declared with a total of 12 patients. 3 confirmed fatalities (adult males) 9 patients transported to local area hospitals. 5 immediate & 4 delayed. PIO onscene. pic.twitter.com/k8txxNqZfL — Long Beach Fire (CA) (@LBFD) October 30, 2019

Luna said there were various reasons given for the party. One person said it was a Halloween party. Another person said it was an office party.

"In our preliminary investigation it appears most of the victims were from outside the city," Luna said. "And it appears that a number of the victims did work at the same location."

Luna said the department had 100 police employees out at the site of the shootings overnight.

"Our homicide detectives are on the scene searching for clues to the gunman," Luna said. "They're also searching the neighborhoods around the shooting for any cameras or video footage that will help us identify these coward or cowards who did this shooting. What kind of coward walks up to an apartment and starts firing into an apartment full of people indiscriminately?'' he asked.

Luna also begged the public to call police with any information that will help them identify the shooter or shooters.

"I know someone out there knows something that can help us. Please call us," Luna said. "This is a horrific and sad day in our city," Mayor Robert Garcia tweeted Wednesday. "We have 3 dead and multiple injured in an act of tragic gun violence. The LBPD is working hard - please keep the victims and their families in your thoughts."