The decision comes amid heightened law enforcement concern about the violent film, with people wondering if it will incite violence in the society.
The department said it has not received any specific threats about the movie, but encouraged moviegoers to be vigilant, reports variety.com.
"The Los Angeles Police Department is aware of public concerns and the historical significance associated with the premiere of 'Joker'. While there are no credible threats in the Los Angeles area, the department will maintain high visibility around theaters when it opens," said department spokesman Josh Rubenstein.
In 2012, a shooter killed 12 people and injured 70 others at a midnight screening of "The Dark Knight Rises" in Aurora, Colorado.
In fact, families of some of the victims have raised concerns about "Joker", in which actor Joaquin Phoenix will be seen playing the character as a depressed loner whose failures as a stand-up comedian provoke him to go on a violent rampage. The Warner Bros. film is about how Arthur Fleck became Joker.
The studio on Tuesday said that the film is not an "endorsement of real-world violence of any kind".
On Thursday, Sandy and Lonnie Phillips, whose daughter Jessica Ghawi was killed in the Aurora shooting, responded to the studio's statement, urging the studio and its parent company, AT&T, to "put its money where its mouth is and announce that it will no longer provide political donations to candidates and lawmakers who stand in the way of gun reform".
Several cinema chains have declined to discuss specifics surrounding their security protocols. However, sources said that discussions are taking place about the best ways to ensure guests' safety as the controversy around the film builds.
The film will open in India on October 2.
( With inputs from IANS )