About 100 of the passengers on the Malaysia Airlines flight that was shot down over the Ukraine on Thursday were reportedly AIDS scientists and researchers heading to Australia for a conference.

A prominent AIDS researcher and others en route to the 20th International AIDS Conference in Melbourne, Australia, are among the victims in the crash of a Malaysia Airlines jet shot down Thursday over eastern Ukraine.

All 298 aboard Malaysia Airlines Flight 17 were killed. More than half of those on the plane, which was flying from Amsterdam to Kuala Lumpur, Malaysia, were from the Netherlands, officials said. Dozens of Australians and Malaysians also were on the plane, officials said.

One American, Quinn Lucas Schansman, who had dual Dutch and U.S. citizenship, was killed in the crash, according to the White House.

Among the dead: Dutch researcher Joep Lange, a former president of the International AIDS Society, whose death was confirmed Thursday by the Kirby Institute at the University of New South Wales in Australia.

“Joep had an absolute commitment to HIV treatment and care in Asia and Africa,” professor David Cooper said in a statement. “The joy in collaborating with Joep was that he would always bring a fresh view, a unique take on things, and he never accepted that something was impossible to achieve. Our joint work in Bangkok, the HIV-NAT center [a Netherlands-Australia-Thailand collaboration], will stand as his legacy.” 

The exact number of passengers who were on their way to attend the IAS conference was unconfirmed, according to a statement from the organization, but more researchers and HIV/AIDS activists were believed to be on board. 

"At this incredibly sad and sensitive time the IAS stands with our international family and sends condolences to the loved ones of those who have been lost to this tragedy," the statement says.

Australian newspapers reported that conference attendees had been told the toll was high, with about 100 on the plane tied to AIDS research.

As of Friday morning, Malaysia Airlines officials said they were still working to confirm the nationalities of four passengers aboard the aircraft. 

The information that an American citizen was on the plane was announced Friday by President Obama during his remarks about the crash.

In a statement released late Thursday, White House Press Secretary Josh Earnest said: "We continue to seek information to determine whether there were any American citizens on board."

"It is critical that there be a full, credible and unimpeded international investigation as quickly as possible," he said.

The latest figures issued by Malaysia Airlines bumped up the previously reported death toll of 295 people, possibly to include three infants now said to have been on the flight.

Here is the listing of passengers by country, according to the Malaysia Airlines release:

  • Netherlands, 189
  • Malaysia, 44 (including 15 crew members and two infants)
  • Australia, 27
  • Indonesia, 12 (including one infant)
  • Britain, 9
  • Germany, 4
  • Belgium, 4
  • Philippines, 3
  • Canada, 1
  • New Zealand 1
  • Unverified, 4

Officials said they were working to notify families. 

In a statement released earlier, the Netherlands' King Willem-Alexander said he was "deeply shocked" at the news of the crash.

"Just like the rest of the Netherlands, my wife and I follow the news to the minute and we hope to have more clarity soon," said Willem-Alexander. "We offer or deepest sympathy to the families, friends and colleagues of the victims and to those who are still uncertain if their loved ones were on board the plane."

Malaysian Prime Minister Najib Razak told reporters it had been "a tragic day, in what has already been a tragic year, for Malaysia," alluding to the disappearance of Malaysia Airlines Flight 370 in March. 

"If it transpires that the plane was indeed shot down, we insist that the perpetrators must swiftly be brought to justice," Najib said.

Follow @MattDPearce for national news