BERLIN, May 16 (Reuters) - European Commission Vice President Valdis Dombrovskis urged the Greek government in a German newspaper interview to speed up its reform efforts and said this was an essential prerequisite for further aid payments.
"Greece is today undoubtedly one of biggest concerns in the euro zone," he said according to a pre-publication copy of an article due to be published in German newspaper Bild on Saturday.
"We've lost a lot of time. Now the negotiations are gathering momentum but we need to step on it. Only once Greece has completed the next step of the reform programme can the last aid payments flow."
He also called on Athens to strengthen reform efforts and said there had been failures in important areas: "There has been progress in some areas but Greece must do even more, especially in terms of consolidating public budgets and in terms of pensions and the labour market." (Reporting by Michelle Martin; Editing by Christian Plumb)