Police are investigating if New York socialite Ivana Trump died after falling down stairs in her Upper East Side home.

Ms Trump, the first wife of former US president Donald Trump, was found dead in her townhouse on Thursday afternoon (local time).

Police sources say Manhattan paramedics, responding to a call for cardiac arrest, found the 73-year-old unconscious and unresponsive at the bottom of a set of stairs.

She was reportedly late for her regular hairdressing appointment, a day before heading to St Tropez on holiday.

The police are investigating whether Ms Trump fell and, if any fall contributed to her death, the sources said. A medical examiner will determine her cause of death.

Mr Trump confirmed his former wife had died in a post on his Truth Social platform early on Friday (Australian time).

“I am very saddened to inform all of those that loved her, of which there are many, that Ivana Trump has passed away at her home in New York City,” he wrote.

The Fire Department of New York said it could not reveal identities but confirmed in a statement that paramedics had responded to a call for cardiac arrest and found a 73-year-old woman dead in the Upper East Side apartment where Ivana Trump lived just after 12.39pm (New York time) Thursday.

Donald and Ivana Trump married in 1977 and divorced in 1992. They had three children together: Donald jr, Ivanka and Eric.

Eric is the only one of the family to have been seen publicly since news of Ms Trump’s death emerged. He was seen leaving her townhouse on Thursday afternoon, telling the assembled media it was “a very sad day”.

“Ivana Trump was a survivor. She fled from communism and embraced this country. She taught her children about grit and toughness, compassion and determination,” the Trump family said in a statement earlier.

Ivanka Trump remembered her mother as “brilliant, charming, passionate and wickedly funny” on Friday, sharing a childhood photo of the pair together.

“She lived life to the fullest – never forgoing an opportunity to laugh and dance,” Ivanka said.

“I will miss her forever and will keep her memory alive in our hearts always.”

Tweet from @IvankaTrump

A former model who once trained for the Czechoslovakian junior national ski team, Ivana Trump played a role in building up the Trump media image in the 1980s, when they were one of New York City’s most prominent power couples.

Their divorce, which came after Mr Trump’s highly publicised affair with Marla Maples, whom he later married, was fodder for the New York tabloids.

While Mr Trump took the credit for his early success breaking into the highly competitive Manhattan real estate market, his then wife played an important role in building the family business soon after their marriage, the New York Times reported.

She worked alongside him in developing Trump Tower, his signature building on Fifth Avenue in Manhattan, and other high-profile projects such as the Trump Taj Mahal Casino Resort in Atlantic City, New Jersey, the Times said.

Ms Trump was the vice president for interior design for the Trump Organisation and managed the historic Plaza Hotel, which Mr Trump acquired in 1988, all while raising their three children.

“No matter how busy I was, I had breakfast with my children every day. I sat with them at dinner every night and helped them with their homework (I loved algebra) before going out in a Versace gown to a rubber-chicken charity event,” Ivana Trump wrote in her memoir, Raising Trump.

“The kids and I celebrated, travelled, and grieved together. Our bond was, and is, our most valuable possession.”

She became an icon in her own right, dripping with 1980s style and elegance, complete with accent and her signature beehive hairdo.

The couple split in 1992, but were on good terms later in life – even appearing in a 1995 TV ad together for Pizza Hut.

Ms Trump also appeared in the 1996 hit film The First Wives Club with the now-famous line, “Ladies, you have to be strong and independent, and remember, don’t get mad, get everything”.

She is survived by her mother, her three children and 10 grandchildren, the family statement said.

-with agencies