A federal agent who was at a Chicago airport to search a private plane that rapper Juice Wrld and his entourage had arrived in administered an opioid antidote to the performer, who briefly woke up incoherent but later died, authorities said.

The plane carrying the 21-year-old rapper, who was named top new artist at the 2019 Billboard Music Awards in May, and about a dozen other people landed at Midway International Airport at around 2am on Sunday.

Federal agents and city police officers were waiting, acting on a tip that a private plane arriving from Los Angeles was carrying guns and drugs, Chicago police spokesman Anthony Guglielmi said.

During a search in a private hangar, a drug-sniffing dog made a “positive alert” on luggage carts loaded with bags from the plane, Mr Guglielmi said.

Inside, they found multiple bags of suspected marijuana, several bottles of prescription cough syrup, three guns, metal-piercing bullets and a high-capacity ammunition magazine, he said.

Juice Wrld performing at Wireless Festival
Juice Wrld performing at Wireless Festival (Isabel Infantes/PA)

The rapper, whose real name was Jarad Higgins and who was from the Chicago suburb of Homewood, went into convulsions during the search.

One of the agents administered Narcan after the rapper’s girlfriend said he had been taking Percocet, an opioid painkiller, Mr Guglielmi said.

Higgins woke up but remained incoherent, the Chicago Tribune reported. He was rushed to Advocate Christ Medical Centre in Oak Lawn, where he was pronounced dead.

A post-mortem examination was completed on Monday but toxicology test results were still pending, the medical examiner’s office said. Foul play is not suspected.

None of the dozen or so people on the plane admitted to carrying the drugs, but detectives were conducting a forensic analysis to determine which bags belonged to which passengers, Mr Guglielmi said, adding that two security guards on the plane were arrested on gun charges.