Following a deadly shooting at a mansion party, Los Angeles Mayor Eric Garcetti is going after people throwing illegal large house parties during the COVID-19 crisis, vowing to have the water and power turned off.

“While we have already closed all bars and nightclubs, these large house parties have essentially become nightclubs in the hills,” said the mayor during a Wednesday afternoon news conference.

Garcetti said the Los Angeles Department of Water and Power will cut off service within 48 hours if the LAPD verifies that there have been violations at a home.

“We will not act lightly, but we will act,” he added.

Los Angeles County director of public health Barbara Ferrer had said earlier Wednesday afternoon at a separate new conference that the parties were illegal.

“These parties and gatherings hurt all of us,” said added. “We ask that everyone make good decisions. Don’t host large parties and don’t attend one if you’re invited.”

The actions came after a Monday night party that drew hundreds of people to a mansion in the Hollywood Hills on Mulholland Drive, despite months of pleading from health officials to avoid social gatherings amid the COVID-19 spread. A 35-year-old woman died in a shooting early Tuesday at the party, and four other people were injured. No arrests have been made as of Wednesday afternoon.

In response, the Los Angeles County Department of Public Health issued a legally binding health officer order that prohibits “gatherings, including parties, during this pandemic in order to protect the health and lives of county residents.”

“We urge every resident in Los Angeles County to follow the health officer order and avoid organizing and attending gatherings that include people outside their own household,” the health department said. “The highest risk settings are large in-person gatherings where it is difficult for individuals to remain spaced at least six feet apart and where face coverings are not worn. The consequences of these large parties ripple throughout our entire community because the virus can quickly and easily spread.”