By Jan Strupczewski BRUSSELS (Reuters) - Greece has only days left to reach a cash-for-reforms deal with creditors because it needs to start negotiating a third bailout that would save it from bankruptcy after the current programme ends in June, euro zone officials said on Wednesday. Cut off from markets, Athens is fast running out of cash to pay salaries, service loans and redeem maturing debt. The 240 billion euro bailout from euro zone governments and the International Monetary Fund, under which Athens could still get some money, expires at the end of June. "The financing of the Greek government is not sustainable without a third programme, additional financing," a senior euro zone official said ahead of a meeting of euro zone deputy finance ministers on Wednesday.