Greece was forced to tap into an emergency account in order to meet a debt repayment of 750 million euros ($845 million) due Tuesday to the International Monetary Fund, a central bank source told AFP.

"That was an initiative by the Bank of Greece's governor to break the deadlock," said the source, a day after Greek Finance Minister Yanis Varoufakis warned that his country risked running out of cash in two weeks if no deal was done by then with its international creditors.