At least two people were killed and more than 20 injured in Miami early on Sunday as attackers opened fire on concertgoers outside a banquet hall. It was the city’s second deadly mass shooting in little more than 24 hours. A police spokesman said the shooting happened in the Hialeah area when three people got out of a white SUV and began firing on a line outside the El Mula banquet hall. The attackers, whom witnesses said were wearing ski masks and hoodies, used assault rifles and a handgun, authorities said. “These are cold-blooded murderers that shot indiscriminately into a crowd and we will seek justice,” the Miami-Dade police director, Alfredo Ramirez, said in a tweet. “This is a despicable act of gun violence, a cowardly act,” he told the Miami Herald. “This type of gun violence has to stop. Every weekend it is the same thing. This is targeted, this is definitely not random.” No suspects were in custody and authorities indicated they expected the death toll to rise. Marcus Lemonis, a Miami businessman and CNBC television host, offered a $100,000 reward for information leading to a conviction. On Friday night, a drive-by shooting in Wynwood left one dead and six wounded. Authorities were alerted by ShotSpotter, an audible detection system that relays the sound of gunfire. A law enforcement source said officers who arrived to find victims lying in the road outside the rented party venue likened that scene to “a war zone”. With almost all pandemic restrictions lifted, visitors have swelled numbers in Miami, a popular vacation destination, for the Memorial Day weekend and the Urban beach week hip-hop music festival. Police have not said if they believe the shootings are linked, but said that it appeared the victims were targeted in both attacks. After the Friday incident, detectives found shell casings from at least two types of weapon. In the Sunday incident, authorities said, eight wounded were taken to hospital by ambulance, at least three in critical condition. A further 12 people went to local hospitals on their own, the Herald reported. TV crews at the scene counted almost 100 evidence markers, a likely indicator of the number of shots fired. Angela Green, whose 24-year-old son was at the concert, told reporters at Jackson Memorial hospital he was shot in the stomach but was expected to survive. “He called us frantic, saying he had been shot, that it hurts and that he loves us,” Green said. “My husband was like, ‘No, stay with us.’ He said the guys came with ski masks and hoodies and just started shooting up the crowd.” Art Acevedo, chief of the Miami police department, a separate jurisdiction to Miami-Dade detectives investigating the shooting, blamed political inaction for failing to curb gun violence. “We had our own shooting the night before where seven people were shot and one dead,” he told CBS’s Face the Nation. “It’s just an indication of the problem we have with the scourge of gun violence in this country that we need to do much more at a federal level to stop. “We need universal background checks. We need to make burglarising licensed gun stores a federal crime with mandatory sentencing. And we need the federal government and both sides to address this issue because without legislation, without certainty as it relates to holding these criminals accountable, we’re never going to get through the summer without much more death and destruction.” Gun control is stalled in the divided US Senate, following the passage of two bills by the House. Joe Biden announced in April his own series of executive orders designed to address the “international embarrassment” of gun violence in America. A Guardian database published last week details every mass shooting in the US since 2014. Ramirez told the Herald he was concerned by levels of gun crime in Miami. “It is very difficult to stop a small amount of individuals who want to go out there and commit murder, and it takes all of us to stop this,” he said. “We really have to put the work in this summer to keep our children and community safe.”