By SUSANNAH CULLINANE

Two people were killed and at least another dozen were injured as shots rang out at a house party in Illinois where people were gathering for Halloween.

It was one of at least 11 mass shootings in the US over the holiday weekend, including several at places where crowds had assembled.

The violence left at least 12 people dead and another 52 injured, according to CNN reporting and an analysis of data from Gun Violence Archive and local news and police reports. CNN defines a mass shooting as an incident with four or more people killed or wounded by gunfire, excluding the shooter.

The number of mass shootings in the US increased during the coronavirus pandemic. There have been 599 mass shootings so far this year, according to the archive. There were 611 in 2020 and 417 in 2019, the group said.

The increase in mass shootings during the pandemic is consistent with the notion that the violence may be influenced by social and economic factors, researchers have said.

Over the weekend, gunfire erupted at house parties, a boxing event and on the streets. These are the mass shootings that took place across seven states.

Illinois: 3 weekend mass shootings

Two people were killed and at least 12 others were injured in shooting early Sunday at a Halloween party in Joliet Township, Illinois, according to the Will County Sheriff's Office. Joliet is about 40 miles southwest of Chicago. (CNN)

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