US rapper Travis Scott is facing legal action after at least eight people were killed and hundreds injured in a crush at his Texas festival Astroworld.
One injured concertgoer has accused Scott and surprise performer Drake of inciting the crowd, and is seeking $1m (£741,000) in damages.
Neither have commented on the lawsuit.
In a statement following the crush, Scott said he was working to help the families of the victims – the youngest of whom was just 14.
Meanwhile, tributes have been paid on social media to those killed.
“Dancing was her passion and now she is dancing her way to heaven’s pearly gates,” the family of 16-year-old Brianna Rodriguez said in a statement.
The surge began at about 21:15 local time on Friday (02:15 GMT Saturday), when panic broke out as the crowd pressed towards the front of the stage during Scott’s headline set.
Lucas Naccarati told BBC Radio 5 Live that within three minutes of the rapper coming on stage, he “was pretty sure people [were] going to be dying”.
“You couldn’t move, you couldn’t scratch your own face, [that’s how] tight it was,” he said.
In a statement posted to Twitter, Houston police chief Troy Finner said he met with Mr Scott and his head of security “for a few moments” prior to the event.
“I expressed my concerns regarding public safety and that in my 31 years of law enforcement experiences I have never seen more challenges facing citizens of all ages, to include a global pandemic and social tension throughout the nation.”
Mr Finner added that he asked Mr Scott and his team “to be mindful of the team’s social media messaging on any unscheduled events”.
Police in the Texas city have launched an investigation, including looking into separate reports that somebody in the audience was injecting people with drugs.
Several concertgoers had to be revived with anti-drug overdose medicine, including a security officer who police said appeared to have an injection mark in his neck.
Local police declined to comment on the drug investigation to the BBC.
Speaking at an unrelated news conference on Monday, FBI Director Christopher Wray said that while local authorities are leading the investigation, the bureau is providing “technical assistance”.
What do the lawsuits say?
One suit filed by 23-year-old attendee Kristian Paredes accuses Scott and Drake of inciting “a riot and violence”, and claims the venue and entertainment company Live Nation failed to provide adequate security and medical services.
The suit, seeking $1m in damages, says Mr Paredes “felt an immediate push” at the front of the general admission section, before “the crowd became chaotic and a stampede began”.
“Many begged security guards hired by Live Nation Entertainment for help, but were ignored,” it adds.
Mr Paredes is described as having suffered “severe bodily injuries”.
Scott, Live Nation and concert promoter Scoremore are also named in another suit seeking $1m in damages for Manuel Souza. Mr Souza is described as having suffered “serious bodily injuries when the uncontrolled crowd at the concert knocked him to the ground and trampled him”.
Live Nation has not yet commented on the lawsuits but has said it is “working to provide as much information and assistance as possible to the local authorities as they investigate”.
The BBC has contacted the company for comment.
High-profile US lawyer Ben Crump announced on Sunday that he was also representing concertgoers in legal action following the crush.
He filed a lawsuit on behalf of 21-year-old Noah Gutierrez and said he expected to file more for other alleged victims in the coming days. “We will be pursuing justice for all our clients who were harmed in this tragic and preventable event,” Mr Crump said.
It is not the first time that Scott has faced legal action over a concert.
In 2018, he pleaded guilty to a public disorder charge after he was accused of encouraging people to rush the stage at a concert in the US state of Arkansas. According to a local newspaper, he also paid nearly $7,000 (£5,186) to two people who said they were injured at the event.
In his first statement after the crush on Friday, Scott said he was “committed to working together with the Houston community to heal and support the families in need”.
He later posted a video on Instagram encouraging anyone with information about the incident to contact the authorities.