Greece has reached a deal on a multi-billion bailout with its international creditors after marathon talks, a government source said Tuesday.

Greece has reached a deal on a multi-billion bailout with its international creditors after marathon talks, a government source said Tuesday.

"An agreement was reached," the source told AFP, with Finance Minister Euclid Tsakalotos briefly telling reporters that "one or two details" remained to be worked out during the day.

A finance ministry source also told AFP: "The details do not affect the main body of the agreement."

The talks between ministers and the ECB, the International Monetary Fund and the European Stability Mechanism aim to finalize the list of new reforms required of the Greek government in exchange for a lifeline of up to 86 billion euros ($94 billion).

The deadline for Greece to reach an agreement on its third bailout is August 20, when it must repay 3.4 billion euros ($3.7 billion) to the European Central Bank.

Earlier on Tuesday government sources said Athens had agreed on fiscal targets for the next three years.

Athens committed to a primary deficit of 0.25 percent of output in 2015, and a surplus in 2016, meaning that no new fiscal measures will be necessary until then, the source said.

In 2016 the primary surplus -- the balance not including debt service -- will be 0.5 percent, followed by 1.75 percent in 2017 and 3.5 percent in 2018, the source added.

The Greek parliament may vote on the accord on Thursday, after which eurozone finance ministers could be asked to approve it on Friday.