David Cameron warned fellow European leaders of the need for the eurozone to take "decisive action" to ensure stability in a high-level conference call to discuss the Greek crisis.
The Prime Minister spoke for around 45 minutes with German chancellor Angela Merkel, French president Francois Hollande and Italian prime minister Mario Monti about the latest situation.
It was arranged by president of the European Council Herman van Rompuy ahead of the G8 meeting in the US which starts tomorrow and which all of the leaders will attend.
He and EU Commission president Jose Manuel Barroso took part in the talks, which came hours after Mr Cameron issued his starkest warning yet of the dangers posed by the debt crisis in Greece.
A Downing Street spokeswoman said it was a "constructive discussion" about the priorities for the talks among some of the world's wealthiest nations in Camp David.
"He discussed with the others their priorities for G8: the eurozone - including Greece, growth and the importance of expanding trade relations between the US and the EU.
"The Prime Minister emphasised the importance of Greece and the Eurozone taking decisive action to ensure financial stability and prevent contagion," she said.
"He repeated what he had said in his speech earlier today: that there is a need for monetary action to stimulate growth, for structural reform to increase competitiveness in the EU, that the right governance arrangements had to be in place and that countries throughout the Eurozone should take the necessary action to tackle unsustainable deficits."