ATHENS, March 29 (Reuters) - Greece sounded an upbeat tone on Sunday over talks with its European and IMF creditors, which it said were continuing through the weekend as the cash-strapped country races to agree on reforms that will unlock more aid.

The euro zone member will run out of money by April 20, a source familiar with the matter told Reuters on Tuesday, if it does not secure funding from its European partners.

In February, Athens agreed an extension to its 240 billion euro ($261 billion) international bailout but with the money frozen until a set of reforms are decided upon.

"Today the Brussels Group discussions continue in a good climate of cooperation," a Greek government official said, referring to the country's European Union and International Monetary Fund creditors.

"We have agreed that we need to draw up suitable policies which will shift the burden from those on the lowest incomes to those on the highest."

The leftist government, elected in January by Greeks weary of austerity imposed under the bailout, submitted a list of proposed reforms on Friday. It said these would raise 3 billion euros while excluding "recessionary measures" such as wage and pension cuts.

An earlier list of seven reforms outlined in broad terms, ranging from tax evasion to public sector reforms, had failed to impress lenders.

Greece said its reforms were costed and that, once agreed upon, the details would be discussed with its lenders' technical teams in Athens.

Prime Minister Alexis Tsipras told a Sunday newspaper that the country's liquidity problems would be resolved immediately after an agreement and that he sought no rift with Europe.

(1 US dollar = 0.9185 euro) (Reporting by Costas Pitas; Editing by Catherine Evans)