17 over eastern Ukraine a day earlier, with 298 people aboard.
He called on all governments to back the investigation and "to support the Ukrainian government to bring to justice all these bastards who committed this international crime."
Since the Malaysia Airlines jet fell from the sky in eastern Ukraine on Thursday, Russia and Ukraine -- which routinely uses the word "terrorists" to describe pro-Russian separatists -- have traded blame and accusations.
"Terrorists have killed almost 300 persons with one shot," Ukrainian President Petro Poroshenko said Thursday. "Among them are women, children, citizens of different countries of the world."
Russian President Vladmir Putin pointed the finger back at Ukraine, blaming its recent tough military operations against separatists for the volatility in the region.
Yatsenyuk called for a U.N. Security Council meeting to be held and for all nations to do everything they could to stop what he said was not now just a war in Ukraine or Europe, but a "war against the world."
Malaysian Transport Minister Liow Tiong Lai said Friday that if reports that Malaysia Airlines Flight 17 was shot down were confirmed, "it would contravene international law, and be an outrage against human decency."
Speaking to reporters in Kuala Lumpur, he added, "Malaysia condemns any such action in the strongest possible terms, and calls for those responsible to be swiftly brought to justice."
The minister offered his condolences to the families of those aboard the downed plane and said Malaysia would give its "full support" to them.
More than half those who lost their lives were from the Netherlands, from where the flight left for Malaysia.