LINCOLN, Neb. (AP) — Two people were killed and 20 others were injured after a crash that sent two cars careening into a crowd of bystanders at an annual Memorial Day weekend “cruise” night in Nebraska’s capital, police said Monday.

The Lincoln Police Department (LPD) tweeted early Monday morning that the two people who were killed had been inside one of the cars involved in the Sunday night crash. Both victims were female, ages 20 and 22. In a separate tweet, the police confirmed that among the others who sustained injuries, one victim had life-threatening injuries, while the others sustained less serious injuries.

According to a Facebook post made by the LPD, this crash happened Sunday night at 10:47 p.m. when a black Ford Taurus was traveling westbound on O Street when it struck a white Toyota Corolla that was facing east. Both vehicles were forced into the north sidewalk of O Street, west of North 52nd Street, striking multiple people where crowds were standing and seated to observe the event.

A witness told the Lincoln Journal Star that a speeding car crashed into another vehicle attempting a turn at an intersection. Hubka said both vehicles jumped the curb and struck several people standing between the street and a parking lot.

Details of the event are not clear. O Street has been a popular spot for cruisers over the Memorial Day weekend and spectators typically gather to watch from business parking lots. Authorities said that some drivers have attempted dangerous maneuvers to excite the crowd, such as burnouts and speeding.

Law enforcement promised to have an increased presence this year. None of the officers assigned to monitor the event witnessed the crash, but police reached the scene within a minute.

This is an ongoing investigation. The LPD does not believe or have any evidence to indicate that this was an intentional act.

“The Lincoln Police Department offers their condolences to the family and friends of those who were killed as a result of this incident. We will work tirelessly to determine what occurred and hold those responsible for this tragedy accountable,” read the Facebook post.

If anyone has any information about this incident or witnessed the crash, the LPD is asking them to come forward, including video or photographic evidence. To contact LPD, call 402-441-6000 or Crime Stoppers at 402-475-3600.

The Associated Press contributed to this article.