A small plane carrying American tourists to a golf outing crashed in a ball of flames into an Australian shopping mall just seconds after takeoff from Essendon Airport in suburban Melbourne.

All five on board were killed. The mall, next to a freeway, was closed when the plane went down about 9 a.m. Tuesday local time.

The four passengers were all from the U.S., the State Department confirmed to ABC News. The pilot of the chartered plan was Australian. Their identities were not officially released as of Tuesday night, though tributes from relatives began to appear on Facebook.

The Americans were heading to a golf course on Tasmania’s King Island when the twin-engine Beechcraft-200 King Air crashed. U.S. Embassy officials went to the scene, The Sydney Morning Herald reported.

A retail outlet is ablaze after a light plane crashed at Essendon Airport, in Melbourne's north https://t.co/ojWJRoizoO pic.twitter.com/8QzT96t3FZ — ABC News (@abcnews) February 21, 2017

“We extend our deepest condolences to the families and loved ones of all those who died in today’s tragic crash,” a a spokeswoman for the U.S. Embassy in Canberra told Melbourne’s Herald Sun.

The pilot, Max Quartermain, 63, owned the air charter company, Corporate and Leisure Aviation, with his wife.

JUST IN: Four U.S. citizens killed in deadly Melbourne plane crash, State Department confirms pic.twitter.com/IKq6pkfNRI — NBC News (@NBCNews) February 21, 2017

It was the worst aviation disaster in 30 years in the state of Victoria.

Victoria Police Assistant Commissioner Stephen Leane said at a news conference that the tragedy could have been far worse with more victims on the ground had the shopping mall been open.

Quartermain issued two mayday alerts just after takeoff and appeared to attempt to veer to return to the airport almost immediately. Officials suspect catastrophic engine failure, but the Australian Transport Safety Bureau is conducting an investigation.

A shaken witness told The Sydney Morning Herald that she saw a “huge fireball and black smoke” in the sky. She could see a section of the mall in flames.

.@theheraldsun nasty stuff. I saw a yellow and red fiery ball explode then black plumes of smoke pic.twitter.com/gDTQESftMv — Mïkey Cahîll (@JoeyLightbulb) February 20, 2017

Victoria Premier Daniel Andrews said it was a “desperately sad day.”

“Our thoughts, our prayers, our best wishes and our support go to all of those who have been caught up in this,” he added. “We are currently reaching out to their families to provide people with the support they need to try and comfort them at such a horrible moment.”

Two adjacent freeways littered with debris and the shopping mall remained closed Tuesday night.