THE HAGUE — International passengers from all walks of life, from a prominent AIDS researcher and soccer fans to a nun and a florist, were aboard Malaysia Airlines Flight 17. The Boeing 777 was carrying 298 people when it was shot down over eastern Ukraine on Thursday in eastern Ukraine, sending shockwaves around the world from Malaysia to the Netherlands. Relatives, friends and colleagues paid tribute Friday to victims even before the airline released their names as it scrambled to contact the next of kin of the victims. For one Australian family, the Ukraine crash represented an almost unbelievable double tragedy. Kaylene Mann's brother Rod Burrows and sister-in-law Mary Burrows were on board Malaysia Airlines Flight 370 when it vanished in March. On Friday, Mann found out that her stepdaughter, Maree Rizk, was killed on Flight 17. “It's just brought everyone, everything back,” said Greg Burrows, Mann's brother. “It's just ... ripped our guts again.” Several passengers were traveling to Melbourne, Australia, for the 20th International AIDS conference, which was starting Sunday. The Academic Medical Center hospital in Amsterdam said in a statement that two of its staff, including renowned AIDS researcher Joep Lange, a former president of the International AIDS Society, and his colleague Jacqueline van Tongeren were believed to have perished. “Joep was a man who knew no barriers,” the hospital said. “He was a great inspiration for everybody who wanted to do something about the AIDS tragedy in Africa and Asia.” Glenn Thomas, World Health Organization spokesman, traveling to the conference was also killed. Most of the victims — at least 173 — were Dutch. The flight set off for Amsterdam's Schiphol Airport in the country's school summer vacation period and was heading for the Malaysian capital, Kuala Lumpur. In the close-knit fishing town of Volendam, near the Dutch capital, flowers were laid outside a florist's shop whose owner and her boyfriend also were believed to be among the victims. Dutch activist Pim de Kuijer, once a political intern of former Dutch lawmaker Lousewies van der Laan, was also among the dead. On Twitter, Van der Laan called him “a brilliant, inspiring and caring activist fighting for equality and helping AIDS victims around the world.” In Kuala Lumpur, a distraught Akmar Mohamad Noor, 67, said her older sister was coming to visit the family for the first time in five years. “She called me just before she boarded the plane and said, ‘See you soon,'” Akmar said. World leaders demanded an international investigation into the shooting down of a Malaysian airliner over eastern Ukraine in a tragedy that could mark a pivotal moment in the worst crisis between Russia and the West since the Cold War. Two US officials said Washington strongly suspected the Malaysian Airlines Boeing 777 was downed by a sophisticated surface-to-air missile fired by Ukrainian separatists backed by Moscow. Makeshift white flags marked where bodies lay in corn fields and among the debris. Others, stripped bare by the force of the crash, had been covered by polythene sheeting weighed down by stones, one marked with a flower in remembrance. The scale of the disaster could prove a turning point for international pressure to resolve the crisis in Ukraine, which has killed hundreds since pro-Western protests toppled the Moscow-backed president in Kiev in February and Russia annexed the Crimea peninsula a month later. While the West has imposed sanctions on Russia over Ukraine, the United States has been more aggressive than the European Union. Analysts say the response of Germany and other EU powers to the incident — possibly imposing more sanctions — could be crucial in deciding the next phase of the standoff with Moscow. Kiev and Moscow immediately blamed each other for the disaster, triggering a new phase in their propaganda war. The plane crashed about 40 km from the border with Russia near the regional capital of Donetsk, an area that is a stronghold of rebels who have been fighting Ukrainian government forces and have brought down military aircraft. Leaders of the rebels' self-proclaimed Donetsk People's Republic denied any involvement and said a Ukrainian air force jet had brought down the intercontinental flight. Russia's Defense Ministry later pointed the finger at Ukrainian ground forces, saying said it had picked up radar activity from a Ukrainian missile system south of Donetsk when the airliner was brought down, Russian media reported. The Ukrainian security council said no missiles had been fired from the armories of its armed forces. The Ukrainian government released recordings it said were of Russian intelligence officers discussing the shooting down of a civilian airliner by rebels who may have mistaken it for a Ukrainian military plane. The United States called for a ceasefire to allow access to the crash site. The plane's two black boxes — voice and data recorders — were quickly recovered, but since the crash site was in rebel hands it was unclear who would analyze them and whether they could in any case determine who fired the missile. Further complicating any investigation, local people were seen removing pieces of wreckage as souvenirs. The condition of the metal can indicate if it has been struck by a missile. More than half of the dead, 173 people, were Dutch. Forty-four were Malaysian, 27 Australian, 12 Indonesian, nine British, four German, four Belgian, three Filipino and one each from Canada, New Zealand and Romania. All 15 crew were Malaysian. Nationalities of the others aboard were unclear. — Agencies