Eight people were arrested for theft, affray and gun possession offences during a police crackdown in Liverpool.
Four teenagers were arrested on firearms offences on Saturday night after a car was stopped in Netherton, north Liverpool.
Three 18-year-olds and a 17-year-old were arrested on suspicion of possession of firearms, an air rifle and an offensive weapon after a Ford Fiesta was stopped by police.
Merseyside Police have cracked down on crime this weekend, recovering £16,000 cash and designer clothes alongside arrests.
Some £5,000 cash was found hidden in the undergrowth of a front garden in Seaforth, North Liverpool on Saturday morning. A search of the property revealed a further £11,000 with a haul of designer clothing and shoes worth an estimated £30,000.
On Saturday night, a 27-year-old was arrested in the area on suspicion of theft of a motor vehicle, dangerous driving and having no insurance after scrambler bikes and a quad bike were seen by patrols driving around at high speeds without lights.
Three people - a 25-year-old man, a 29-year-old man and a 26-year-old woman - were also arrested for affray following an incident in Stoneycroft, central Liverpool on April 8. All three have been bailed pending further inquiries.
Merseyside Police warned criminals that they could "expect a knock on their door" in the future.
Detective Superintendent Richie Salter said: "We are aware of a number of incidents of disorder involving firearms in the past week.
"I want to make it clear that this type of behaviour will not be tolerated and we will continue to take action against those involved in serious and organised crime.
"We will continue to disrupt criminal activity and relentlessly pursue those who are involved in criminality to take them off our streets.
"I want to reassure the law abiding members of the public that our commitment to tackling gun and serious crime is as strong as ever.
"Anyone who is involved in this type of criminality can expect a knock on their door in the coming days, weeks and months."