Two teenagers aged 15 and 16 were arrested on Sunday on suspicion of involvement in a shooting that left five members of the same family dead in the city of East St. Louis in the US state of Illinois, according to the Guardian, citing state police.

Illinois State Police Superintendent Brendan Kelly said at a press conference that the suspects were taken into custody at Holten Nature Park east of the city and that no formal charges have yet been brought against them. He described the attack as a "targeted mass shooting".

In addition to the five killed, two other people were injured in the attack and were transported to a hospital in neighbouring St. Louis in Missouri. Police released the identities of the victims: the deceased family members were between 21 and 74 years old. According to Kelly, at least one of the suspects is related to at least one of the victims, and the shooting took place at three locations in the city. There were no random bystanders among those killed.

Kelly declined to comment on how the minors obtained weapons. Illinois has some of the strictest gun laws in the US, but East St. Louis lies on the border with Missouri, a state that does not require permits to purchase or carry firearms.

According to data from the Gun Violence Archive cited by the Guardian, this is the twelfth mass killing in the US this year, and since the beginning of the year the country has recorded more than 240 mass shootings, defined as attacks with at least four people killed or injured.