The Russian ambassador has denied pro-Russian separatists were responsible for shooting down Malaysia Flight MH17, in which 298 people were killed including at least 28 Australians.

Foreign Minister Julie Bishop revealed the denial after she had summoned and met with ambassador Vladimir Morozov in Sydney on Friday.

Ms Bishop described the crash as an "unspeakable crime" and called for Russia and Ukraine to support a full investigation through the UN Security Council.

She said Mr Morozov "provided that unqualified support...and assured me Russia would do what it could to find those responsible".

"I also asked him about whether Russian equipment – surface to air missiles or the like – could have been involved and he said not to his knowledge," Ms Bishop said.

It had previously been reported that 27 Australians had died, but Ms Julie Bishop says 28 Australians are now known to have died and fears that number may rise.

Earlier on Friday, Prime Minister Tony Abbott said it appeared Russian-backed rebels were responsible for shooting down the commercial flight over eastern Ukraine and was strongly critical of "the bullying of small countries by big ones".

Addressing Parliament on Friday morning, Mr Abbott said Australia would seek a binding resolution through the United Nations Security Council for an impartial investigation with full access to the site, debris, black box and ‘‘all individuals who might be in a position to shed light on this terrible event”.

Mr Abbott described the disaster as ''a grim day for our country and it's a grim day for our world''.

''As things stand, Madam Speaker, this looks less like an accident than a crime,'' he said.

''And, if so, the perpetrators must be brought to justice.''

Flags on government buildings will be flown at half-mast as a mark of respect to those killed, and a national commemorative service and national day of mourning will be held at a later date.

Mr Abbott said a Department of Foreign Affairs team was preparing to leave for Kiev and they would offer counselling and assistance and bodies would be repatriated to Australia as soon as possible.

He said: ''We owe it as well to the families of the dead to find out exactly what has happened and exactly who is responsible''.

''Our hearts go out to the families of all the dead,'' Mr Abbott said.

''Our thoughts and prayers especially are with the families of the Australian dead.

''We can't restore them to life but we can and will do everything to support them in this sad and bitter time because that is the Australian way.

"Let me conclude with this: The bullying of small countries by big ones, the trampling of justice and decency in the pursue of national aggrandisement and reckless indifference to human life should have no place in our world."

The National Security Committee, made up of Mr Abbott, Warren Truss, Ms Bishop, Joe Hockey, George Brandis, David Johnston and Scott Morrison, met in Canberra on Friday morning to discuss the incident.

Other world leaders have quickly responded to the tragedy, but have been wary of apportioning blame. US President Barack Obama said his nation's top priority determining whether American citizens were on board. Mr Obama said the crash "looks like it may be a terrible tragedy" and offered his thoughts and prayers to families of the victims, "wherever they call home".

German Chancellor Angela Merkel, who has worked closely with Mr Obama on sanctioning Russia for its Ukraine policies, would not place any blame, but said in a statement that if reports the plane was shot down prove true it would be a "tragic escalation" in the conflict.

French President Francois Hollande, speaking in Abidjan, Ivory Coast, said it's essential that the "truth be established".

At a press conference early on Friday a sombre Malaysian Prime Minister Najib Razak, dressed in black, said the world was ‘‘united in grief’’ over the disaster.

‘‘This is a tragic day, in what has already been a tragic year, for Malaysia,’’ he said. As questions were raised over why the passenger jet was flying over an active war zone, Najib said international air authorities had deemed the flight path safe.

Russia said its president, Vladimir Putin, asked the Malaysian Prime Minister "to convey his deepest sympathy and support" to the families of those aboard the Malaysia Airlines jet.

Mr Putin said he had also asked Russian military chiefs to ‘‘provide all necessary help to shed light on this criminal act’’. But he also put responsibility for the disaster squarely on Ukraine.

‘‘There is no doubt that the country on whose territory this terrible tragedy happened bears responsibility,’’ said Putin, quoted by Ria Novosti news agency. ‘‘This tragedy would not have happened if there was peace in the country, if military operations had not resumed in the south-east of Ukraine,’’ he said.

Opposition Leader Bill Shorten said the news Australians woke up to on Friday morning was ''worse than shocking''.

''It is debilitating, bewildering, with bewildering losses,'' he told the Parliament.

''Travelling at six miles height, this is unimaginable. This is a violation of the rules of civilisation. It is a tyrannical, wild act and I appreciate that when I rang the Prime Minister this morning he has been most forthcoming and in a time when international events require one to put aside partisan issues.''

Mr Shorten said the tragedy would be felt all over the world.

''Most tragically, there are at least 27 Australians who have been murdered. Mothers and fathers, brothers and sisters, neighbours, colleagues, class mates and teammates.

''They are Australians who would have planned to be at an airport tomorrow night to collect friends and family.

''Amongst them, some of the world's leading AIDS experts. We grieve for all of them and it does reach beyond Australian shores.''

Earlier on Friday Mr Abbott said it seemed certain that Malaysia Airlines flight MH17 was ''shot down'', saying if this was the case it would be an ''unspeakable crime''.

The plane was en route to Kuala Lumpur from Amsterdam when it is believed that it was brought down over separatist-controlled eastern Ukraine.

Foreign Affairs Minister Julie Bishop said the plane was a flight due to connect to Australia with a number of people on board believed to have been on their way to Melbourne for a global AIDS conference at the weekend.

''I can confirm 27 passengers on that flight were Australian nationals,'' Ms Bishop said. ''We've been able to independently verify that.''

Mr Abbott told Fairfax Radio 3AW on Friday that if the plane had been shot down by a missile supplied by Russia, then ''Russia bears a heavy share of responsibility'' for the disaster.

''They [the militants] are Russian proxies essentially. This is only happening because Russia wants to stir up trouble,'' he said.

''Now, it's important that we don't make a situation worse, but if, as now seems certain, it has been brought down by a Russian-supplied surface-to-air missile, Russia bears a heavy share of responsibility.''

On Friday morning the Senate paused in silence for passengers believed to have died on the flight.

Government Senate leader Eric Abetz on Friday offered his condolences to family members of those Australians and other passengers who lost their lives.

His sentiment was echoed by Labor Senate leader Penny Wong who expressed shock and grief at the ''heartwrenching'' crash.

Ms Bishop on Friday said Australian officials were seeking permission to access the crash site and would demand a full, independent international inquiry, amid reports Russian separatists have taken the plane's black box.

''Regardless of the circumstances we urge the separatists to co-operate with an investigation into this crash,'' Ms Bishop said. ''If they have taken the black box it must be returned to authorities immediately.

''This incident underlines the urgent need to de-escalate tensions in eastern Ukraine.''

Mr Abbott refused to discuss the possibility of Russia and Mr Putin being banned from attending the G20 summit later this year while the circumstances that led to the tragedy are confirmed.

''The G20 is an economic gathering,'' he said.

''It's not a security gathering. That doesn't mean that security issues are never discussed.

''But the principle purpose of the G20 is to try to ensure the world's largest and most representative economies are working constructively and, where possible, co-operatively for the benefit of all the world's citizens.''

The Department of Foreign Affairs and Trade says it's seeking confirmation from authorities and has set up a hotline - 1300 555 135 - for relatives to call.

with AAP, LA Times

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