The New York clinic where comedian Joan Rivers stopped breathing a week before her death denied ever administering general anaesthesia or conducting a vocal cord biopsy as has been alleged in media reports as contributing to her demise.

It was the first time the Yorkville Endoscopy clinic issued a statement since August 28, when Rivers was rushed to a nearby hospital from the centre with cardiac arrest. She died at age 81 on September 4.

The clinic did not mention Rivers by name but issued the statement hours after New York’s Daily News newspaper reported that an unplanned vocal cord biopsy at the clinic had left the Brooklyn-born comedian unable to breathe.

“A biopsy of the vocal cords has never been performed at Yorkville Endoscopy,” said the clinic, which specialises in gastrointestinal procedures. “General anaesthesia has never been administered.”

The Daily News said Rivers’s doctor, who said he was an ear, nose and throat specialist, asked if he could use the clinic’s instruments when another doctor said he had noticed something on Rivers’s vocal cords, and he was given the go-ahead.

“A biopsy like that should only be done in hospital,” the newspaper quoted the unnamed medical source as saying. “If she had been in a hospital when it happened, she might have been OK.”

The cause of Rivers’s death is still unknown pending further tests.

“The investigation is ongoing,” a department official said earlier this week.

Rivers was known for her brash style, numerous cosmetic procedures that she joked about in her comedy routines, and the catchphrase, “Can we talk?”

Her career as a stand-up comedian, author, talk show host and reality TV star spanned five decades.

Broadway theatres dimmed their marquees for one minute in honour of Rivers, who was nominated for a Tony award in 1994 for Sally Marr .. and Her Escorts, which she wrote. She also appeared in two other Broadway shows.