Joan Rivers' daughter said loved ones are hopeful about the comedian's condition as she remains in hospital three days after going into cardiac arrest at a New York City doctor's office.

Melissa Rivers said in a statement that "we are keeping our fingers crossed".

She is thanking people for expressing their support for the star.

Among the well-wishers are fellow celebrities including two of Joan's co-stars on TV's Fashion Police, Giuliana Rancic and Kelly Osbourne.

The Mount Sinai Hospital said that it had no updates to release on 81-year-old Joan's health.

The star was taken to Mount Sinai on Thursday.

She had spoken the day before at an employee event at Time Inc in New York and spectators there said she had appeared to be well.