The incident took place on Saturday morning in Los Angeles' Benedict Canyon neighborhood, The Los Angeles Times newspaper reported.
The report said that three people were killed inside a vehicle on the street and four were wounded outside.
The suspect or several suspects remain at large, the report also said.
It added that those injured were taken to local hospitals, with two of them remaining in critical condition and two others being in stable condition.
The US legislation allows to keep the arms without registration or having license in 43 states, which presumably, among other things, causes frequent fatal shooting incidents. On Monday, a group of US senators reintroduced a federal Assault Weapons Ban and legislation that would raise the minimum purchase age for assault weapons to 21. US President Joe Biden has called on the Congress to immediately pass the legislation and deliver it to his desk.
Also on Monday, at least seven people were killed and one injured in a mass shooting that occurred at two different locations in the city of Half Moon Bay, California. Another lethal shooting was reported in Oakland, California on Monday evening that left at least one dead and several injured.
According to Gun Violence Archive analysts, there have already been about 40 mass shootings in the United States since the beginning of the year.