French President Francois Hollande said Greece's leaders must show their commitment to reform and Europe must decide on how to help the country as soon as possible after it receives a progress report from Athens' international lenders in October.
Greece must also stay in the euro zone, he added after a meeting with Greek Prime Minister Antonis Samaras on Saturday, echoing comments by German Chancellor Angela Merkel, who held similar talks with Samaras on Friday.
But Hollande, who has taken a softer line than Germany on the need for austerity to help the euro zone rein in its deficits, added that Greece, where unemployment has hit a record 23 percent, must not push its people too far.
"It (Greece) must demonstrate again the credibility of its programme and the will of its leaders to go through with it to the end, whilst ensuring it's bearable for the population," Hollande told reporters.
He said that once the "troika" of the European Commission, European Central Bank and International Monetary Fund lenders have handed in their next report on Greece's fiscal situation, Europe should not hesitate to act.
"Once we have this report, once the commitments ... are confirmed, Europe has to do what it has to do," he said. "That means after the troika report at the European summit in October."
Samaras, whose conservative-led government took power in June promising to fulfil the austerity pledges Greece made to receive its bailout, wants European leaders to give his country more time to push through the unpopular reforms.
He has been hoping for a two-year extension to the budget targets promised under Greece's second, 130 billion euro ($163 billion) bailout from the European Union and International Monetary Fund, as the country struggles through its fifth year in recession.
Germany's finance minister, however, reaffirmed his opposition to giving Greece more time in an interview with the Tagesspiegel on Sunday newspaper, according to advance excerpts.
"More time generally means more money, and that very soon means a new (bailout) programme," Wolfgang Schaeuble was quoted as saying. "That would not be the right way to solve the fundamental problems of the euro zone."
Schaeuble said extending the period of the programme so soon after it was agreed at the end of 2011 would send a bad signal.
"If after just half a year that were no longer to be sufficient, that would not be a confidence-building measure," he said.
Samaras said in a German newspaper interview earlier this week that Greece could stay afloat if it received its next tranche of aid later than October, but will be broke if the money does not arrive.
The Eurogroup of euro zone finance ministers will meet in Luxembourg on Oct. 8 and may discuss the troika's report on Greece and any plans to loosen its bailout terms. EU heads of state and government will then meet in Brussels on Oct. 18-19.
Financial markets have been optimistic that Europe -- and particularly the ECB -- will finally come up with decisive action in a busy month of euro diplomacy in September to resolve the shared currency bloc's sovereign debt crisis.
Spain, the latest hot spot in the 2-1/2-year euro zone debt crisis, is in talks about conditions for aid to bring down its borrowing costs, though it has not made a final decision to request a bailout, sources said this week.
The country has said it would wait until the next ECB meeting on Sept. 6 to hear any details on how the ECB plans to intervene before deciding on any move.
ECB President Mario Draghi signalled earlier this month that the central bank may start buying government debt to bring down crippling Spanish and Italian borrowing costs.
With sources saying Spain may be on the brink of a sovereign bailout, Europe and the IMF are keen to stress the importance of the strict conditions for the aid they extend.
Samaras said that Greece would do whatever it took to get out of the crisis, adding that he had assured the French president Greece was determined to remain in the euro zone, which would show that Europe was capable of solving its problems.
"Some are betting that Greece will not make it. I am here to assure the French president that Greece is determined to make it and it will," he said.
The Greek leader added that economic recovery was crucial to help it meet its targets.
Hollande said that he wanted the question of whether Greece stays in the euro zone or not to stop being an issue.
Merkel on Friday also reassured Samaras that she wanted Greece to stay in the euro zone, but gave no sign of ceding to his pleas for more time to meet the tough terms of Athens' international bailout.
She also stuck doggedly to her policy of deferring to the troika report, though she did say that she and Hollande were in no doubt they wanted Greece to stay in the single currency.
The French and German leaders had coordinated their stance on Greece over dinner in Berlin on Thursday.
Trying to emulate the "Merkozy" partnership under Hollande's predecessor Nicolas Sarkozy, the conservative Merkel and the Socialist French president showed a united front, insisting Greece must meet its targets before any new discussion of terms.