James Gandolfini died after heart attack

The Sopranos star James Gandolfini died following a heart attack, an autopsy has confirmed.

Family friend Michael Kobold told a news conference the actor died of natural causes and that "nothing was found in his system".

He added his body had been released to a funeral director and plans were being made to repatriate him to the US.

Gandolfini had been on holiday in Italy, where he had been due to receive an award at the Taormina Film Festival.

"James came here on vacation meeting his family. He had a wonderful day - he visited the Vatican, he had dinner at the hotel with his son, awaiting the arrival of his sister," Mr Kobold read out in a statement from Gandolfini's family.

"We are all devastated by this loss. James was a devoted husband, a loving father of two children and a brother and cousin you could always count on."

Mr Kobold added, although it can take up to 10 days in Italy to complete the necessary paperwork to repatriate the body, it was hoped the process could be shortened to return Gandolfini to the US by next Thursday.

He added he hoped a funeral would take place in New York by next Saturday.

Earlier, a hospital spokesman said doctors and paramedics spent 40 minutes trying to save the star after he was found in the bathroom of his Rome hotel room and taken to the Policlinico Umberto I hospital.

Dr Claudio Modini told Reuters that as attempts to resuscitate Gandolfini in the ambulance and hospital had failed, he was considered dead on arrival.

"The resuscitation manoeuvres, including heart massage, continued for 40 minutes and then, seeing no electric activity from the heart, this was interrupted and we declared James dead," Dr Modini said.

Under Italian law, medical examiners are required to conduct a post-mortem 24 hours after the body's arrival in the morgue.

Taormina Film Festival organisers Mario Sesti and Tiziana Rocca said they were "deeply saddened" by Gandolfini's death.

"We had heard from James Gandolfini a few hours before and he was very happy to receive this award and to be able to travel to Italy," they said in a statement.

"He was the American actor that better than anyone else has been able to interpret the Italian-American with his personality full of contrasts, ambition, pain, humour. He was the face of the golden age of television, but also a memorable film actor."

They added they would be organising a tribute to his "career and talent".

Meanwhile, Hollywood stars have continued to pay tribute to the actor.

Kathryn Bigelow, who directed Gandolfini in Zero Dark Thirty, said she was devastated by the news.

"James was such an enormous talent, and an even greater spirit. I will be forever grateful for the privilege of working with him, and shall cherish his memories always," she said.

Brad Pitt, who appeared in three films with Gandolfini, called him "a ferocious actor" and said he was "gutted by this loss".

At the time of his death, the actor had been working on upcoming HBO series Criminal Justice, and had two films due out next year - the comedy Enough Said and crime drama Animal Rescue.