BRUSSELS (Reuters) - Greek Prime Minister Alexis Tsipras will not come to Brussels on Friday to continue talks with the country's creditors, an EU official said, complicating an agreement in the cash-for-reforms negotiations. Talks of international creditors with Greece on new funding have been dragging on for four months but have now entered a new, more urgent phase, as Athens is quickly running out of cash without which it may default and leave the euro zone. To speed up talks, Tsipras flew into Brussels on Wednesday evening to meet European Commission President Jean-Claude Juncker but the meeting ended without an agreement although some progress was made, Juncker said. More talks were to tale place on Friday evening, officials said. "There will be no meeting tomorrow. The Greeks last night agreed to send a compromise on how to solve the few outstanding issues. They did not. So tomorrow no meeting is possible," the official said. Greece was supposed to repay a 300 million euro an installment of loan from the International Monetary Fund on Friday, the first of four installments due in June, but told the IMF it would pay everything at the end of the month. "The bundling of payments is not a good sign, it will be difficult from here on," the EU official said. (Reporting By Jan Strupczewski)Join the conversation about this story » NOW WATCH: Here's what 'Game of Thrones' stars look like in real life