Hillary Clinton has warned Vladimir Putin that he has "gone too far" following the shooting down of Malaysia Flight MH17 on Thursday over Ukraine, as America puts pressure on Europe to escalate sanctions against Moscow.
The former US secretary of state and likely 2016 presidential candidate said yesterday that "there does seem to be some growing awareness that it probably had to be Russian insurgents" who shot down the passenger jet.
The the Boeing 777-200, was carrying 298 people from Amsterdam to Kuala Lumpur. Kiev has branded the event an "act of terrorism".
Clinton told American interviewer Charlie Rose yesterday that the crisis should wake Europe up to the threat posed by Putin. "I was recently in Europe. A lot of questions about whether or not Russia was really the aggressor, whether or not Putin was really dangerous, how could that be evaluated," she said.
"From my perspective — and I have the benefit of not being in the government — if there is evidence linking Russia to this, that should inspire the Europeans to do much more."
Her criticism of Putin, the strongest yet from a Wester leader in the wake of the downing of the jet, is a long way from her attempt to "reset" the US relationship with Russia in the early days of the Obama administration.
Clinton said Europe needed to lead the response to the crisis, as it took place in its territory, and put "Putin on notice that he has gone too far and we are not going to stand idly by."
The crash came just one day after President Obama announced tough new sanctions against Russia by way of punishment for its alleged support of Ukrainian separatists. The European Union also agreed a package of new sanctions, but they are not expected to go as far as the US action.
The EU has been criticised for failing to take as tough a line as Washington. Resistance was initially led by Germany which has strong economic links to Russia. And Obama has previously raised concern about France's plan to sell two warships to Moscow - the first time a Nato country has sold such sensitive military equipment to its former Cold War foe.
US vice-president, Joe Biden, said the plane appeared to have been "blown out of the sky". And Republican Senator John McCain said there would be "hell to pay" if it turned out the plane had been shot down by the Russian military or by pro-Russian separatists.
Putin has blamed Ukraine for the crash. "Without question, the state over whose territory this took place, bears responsibility for this awful tragedy," he said.
In London, David Cameron is to chair a meeting of the government's emergency Cobra committee after nine Britons were among the hundreds killed.
According to the airline, there were 154 Dutch passengers, 45 Malaysians, including 15 crew, 27 Australians, 12 Indonesians, four Germans, four Belgians, three Filipinos and one Canadian on board.
Foreign secretary Philip Hammond, who is on only his third day in the job following the prime minister's reshuffle, has called for an international investigation to establish what happened to MH17 when it crashed into territory held by pro-Russian separatists.
Speaking at the Foreign Office following emergency talks with ministers and officials, Hammond said: "We're determined to get to the bottom of understanding what has happened here," he said.
"As yet, we do not have any definitive information about how this incident occurred and I don't want to speculate at this stage. We believe that there must be a UN-led international investigation of the facts."