Flags flew at half mast in Australia on Saturday as the country mourned the more than two dozen Australian victims on the Malaysia Airlines flight that crashed Thursday in Ukraine, killing all of the nearly 300 passengers on board.

Amid US allegations that the plane had been downed by a surface-to-air missile fired by pro-Russian separatists in eastern Ukraine, Australian Prime Minister Tony Abbott had strong words directed at Russia on Saturday. Like US President Barack Obama a day before, Abbott indirectly implicated Russia in Thursday's disaster.

"Australia takes a very dim view of countries which facilitate the killing of Australians, as you'd expect," Abbott said Saturday. "The idea that Russia can wash its hands of responsibility because this happened in Ukrainian airspace just does not stand serious scrutiny."

He said he had been able to speak with Ukrainian President Petro Poroshenko about the incident, but had not spoken with Russian President Vladimir Putin.

Silent treatment from Moscow

Australian Foreign Minister, Julie Bishop, took a similar tone in an interview with the Australian Broadcasting Corporation on Saturday, saying she had been unable to get in touch with her Russian counterparts to discuss the crash.

Efforts to contact Russian Foreign Minister Sergei Lavrov failed because he was on holiday, she was told, and her follow-up requests to speak with a deputy were met with the response that she would "not be able to speak to anybody in the ministry of foreign affairs in Moscow."

Bishop heads to New York on Saturday to represent Australia at the United Nations and support the call for an independent international investigation.

Access to crash site difficult

A number of international teams are either in Kyiv or on their way to begin investigating the circumstances that brought down the Boeing 777. Ukraine has asked for assistance with an investigation from UN, US and European air safety organizations, Boeing, Malaysia and the Netherlands.

Any investigation will hinge on the cooperation of pro-Russian rebels in eastern Ukraine. They control the territory where debris from the plane landed, and have been involved in clashes with Ukrainian military forces since February.

An observer team from the Organization for Security and Cooperation in Europe (OSCE) visited the crash site on Friday, but said there were indications that debris and material had been moved and the site had not been sealed off.

The OSCE's Michael Bociurkiw told a news conference on Friday: "Unfortunately the task was made very difficult. Upon arrival at the site ... we encountered armed personnel who acted in a very impolite and unprofessional manner. Some of them even looked slightly intoxicated." The gunmen claimed to have recovered two flight recorders from the aircraft, however this has not been independently verified.

mz/hc (AFP, AP, dpa)