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.

“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.

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.