Hayden Panettiere found unresponsive after cardiac arrest - report

Hayden Panettiere was reportedly found unresponsive in a South Carolina house after suffering a cardiac arrest.

Emergency services responded to reports of an "unresponsive female", who was later identified as the Heroes actress, at a property in Greenville, South Carolina on Sunday afternoon.

The 36-year-old's friend, who has not been identified, called 911 at 1:51pm to report that she was unresponsive and in cardiac arrest.

In 911 dispatch audio obtained by TMZ and Page Six, officials can be heard discussing an "overdose" and "cardiac arrest" in relation to the report and a responder adding, "CPR is in progress."

However, she could not be revived and was reportedly pronounced dead at the scene at 2:32pm.

Earlier on Monday, a spokesperson for the Greenville Police Department confirmed that they responded to "a report of an unresponsive female" alongside paramedics.

"Upon arrival, medical assistance was administered; however, the individual, later identified as Hayden Panettiere, was pronounced deceased at the scene," the statement to NBC News said.

"The preliminary investigation has not indicated any signs of foul play or suspicious circumstances. An acquaintance of Ms. Panettiere placed the 911 call."

The Greenville County coroner will perform an autopsy on the Nashville star on Monday to determine the cause of death.

Panettiere's father, Skip, announced her death on Sunday, prompting an outpouring of tributes from her co-stars and celebrity friends.

Viola Davis, who worked with Panettiere on the 2016 movie Custody, described her as "gifted" and "an old, wise soul with such a deep heart".

"I wish the world had more time with you because I had a burning curiosity about who you were becoming. I saw this beautiful Phoenix rising from the ashes," she wrote on Instagram. "Your tests became your testimony, and your testimony became your legacy. You will be remembered. Rest well, Hayden. Sending healing prayers to your family, your daughter, and all who loved you. May they always speak your name...."

The likes of Rosie O'Donnell, Kelly Osbourne, Melissa Barrera, David Arquette and Selma Blair also mourned the actress online.

Panettiere is survived by her 11-year-old daughter Kaya.