Riga (AFP) - German Chancellor Angela Merkel said Friday there was still a lot of work needed to reach agreement with Greece on its debt bailout, as tortuous talks drag on amid fears Athens could run out of money.The government of Greek leftist Prime Minister Alexis Tsipras is locked in talks to obtain fresh funding with international creditors who are demanding more tough austerity measures in return.Tsipras met Merkel and French President Francois Hollande late Thursday on the sidelines of the EU-Eastern Partnership summit in the Latvian capital Riga but their discussions produced no breakthrough."It was a very friendly and constructive exchange," Merkel said as she went into the summit Friday."But it is clear, the work with the three institutions has to go on.