Deputy finance ministers and central bankers of the 16-member Euro zone decided that any emergency loans would be made on terms almost identical to standard International Monetary Fund bailouts if Greece needed them, an EU source said.

"A deal has been reached," the source with close knowledge of the discussions told Reuters. "It is almost a carbon copy of International Monetary Fund terms."

But the news brought only momentary relief to credit markets because Fitch Ratings cut Greece's credit rating to BBB-minus, its lowest investment-grade rating, and signaled further downgrades are possible.

New figures published highlighted a deepening recession in Greece that will further aggravate its fiscal problems as the government continued to resist market pressure to seek outside help with its debt crisis.

After investors dumped Greek assets this week due to growing doubts over the euro zone/IMF rescue plan, the risk premium on Greek bonds briefly dipped below 400 basis points over benchmark German Bunds on news of the Brussels deal.