BRUSSELS — Greek leaders scrambled on Sunday to come up with a list of proposed changes to the nation’s austerity program that would be acceptable to their creditors by a Monday deadline, even as they faced a revolt by members of their own radical-left party, angered that the government had bent to demands by Brussels.

An 11th-hour deal reached on Friday by Greece and eurozone finance ministers did nothing immediately to reduce the obligations Greece must fulfill to keep a lifeline of cash coming and avoid insolvency for the heavily indebted government.

The sole concession to Athens was to allow it to propose changes to the requirements agreed to with creditors by the previous Greek governments, in effect allowing Athens to change the shape of its obligations, not reduce them.

While the government of Prime Minister Alexis Tsipras hailed the chance to propose its own overhauls as a victory, the deal represented a steep climb down for his Syriza party, which had vowed to get rid of the current bailout program.

What’s more, Athens will still have to convince its creditors that the alternative measures will not derail the budget. Any proposals must meet the approval of eurozone finance ministers, who are expected to vet them this week. Even if Greece’s creditors and eurozone partners are satisfied with the proposals, the deal still needs approval from the Greek Parliament, as well as other eurozone member parliaments.

Victory or not, the deal agreed to Friday has immediately put Mr. Tsipras in a tight corner at home, where pressure has mounted on him to pare back his government’s austerity program, despite pressure from Brussels.

As the Tsipras government worked Sunday to devise changes to propose, a chorus of lawmakers took to the airwaves and social media to condemn the deal, opening the way to a potentially embarrassing backlash in Parliament in Athens. At least one Syriza lawmaker threatened to resign.

The criticism was accompanied by furious speculation about how any proposed overhauls might affect citizens who voted in large numbers for Syriza, the anti-austerity party, with the express goal of easing hardships linked to the conditions of European loans.

The deal reached Friday allows Mr. Tsipras to ask to drop austerity measures to which the previous government committed but never enforced, such as further cuts to pensions, an increase in a special value-added tax on the Greek islands and the relaxing of restrictions on mass dismissals in the private sector.

In return, Mr. Tsipras and his government are expected to propose other, chiefly structural changes, including some actions that the previous government failed to deliver on, such as a crackdown on tax evasion and corruption.

Such changes, if accepted, might ease the burden on the majority of Greeks who have been hit by austerity over the years, and shift more of it to the rich and privileged who have emerged from the crisis relatively unscathed and who, creditors insist, should shoulder part of the solution.

Indeed, many now expected that the government would propose changes aimed at helping those hit hardest by years of austerity in Greece, perhaps by raising low-income pensions. On Sunday, the changes seemed to be headed in the direction of focusing on a crackdown on tax evasion and corruption, and an overhaul of the public sector, a government official said.

If Greek lawmakers do not like the deal, they can vote it down. The coalition government in Athens has 162 seats in the 300-member House.

Even if the government can navigate the pressures at home, a hazardous series of steps lies ahead before it can gain access to the 7.2 billion euros, or $8.2 billion, Mr. Tsipras is now seeking.

International bailout monitors must conduct a further review of Greek finances before unblocking the rescue funds. Eurozone finance ministers need to assess the proposed overhauls, and it was possible that they could make a decision during a conference call on Tuesday.

But Jeroen Dijsselbloem, the president of that Eurogroup of ministers, could also call another face-to-face meeting on Tuesday, when he is scheduled to address the European Parliament. That parliamentary session is likely to be dominated by the situation in Greece.

Athens secured its agreement with its 18 eurozone peers late on Friday to extend the country’s bailout program with European creditors by four months, winning a financial lifeline and some breathing space.

A few hours later, in a speech to the nation, Mr. Tsipras described the accord as “an important negotiating success in Europe” despite accusations of capitulation from critics inside and outside the government.

But there is little doubt that Mr. Tsipras was forced by eurozone ministers to drop campaign promises to radically reshape or scrap the bailout program after it became apparent his country would probably face capital controls within days and run out of money in weeks.

Yanis Varoufakis, the Greek finance minister, promised not to roll back policies introduced by previous governments and not to introduce any surprise measures during a four-month breathing period.

In one of the bitterest blows for Greece, showing the degree to which trust had eroded between Greece and the Eurogroup during the past several weeks of sniping, finance ministers decided to put €10.9 billion in funds previously part-controlled by Greece to rescue banks into a Luxembourg fund. That fund can release the money only at the request of the European Central Bank.

Even as government officials scrambled to complete the list and an accompanying analysis demanded by creditors, there were indications of internal dissent, with many prominent members of Syriza saying Athens should not give in to creditors.

Giorgos Katrougalos, the minister for administrative reform, told Greek television he would resign if “our red lines were not respected.” He said several of the pre-election pledges that brought Mr. Tsipras to power were not up for negotiation, including the rehiring of thousands of dismissed civil servants.

Manolis Glezos, a veteran Greek leftist, denounced backtracking by Syriza and suggested that the party’s leadership had deceived voters by bending to demands by Brussels and by agreeing to prolong the previous program.

”I apologize to the Greek people because I participated in creating this illusion,” Mr. Glezos, a member of the European Parliament, wrote on a blog, Active Citizens Movement, run by a group within the Syriza party.

Mr. Glezos called on “members, friends and supporters of Syriza” to “react before it is too late” by holding emergency meetings at all levels “to decide if they accept this situation.”

A government official responded that Mr. Glezos “may not be well-informed on the tough and laborious negotiation, which is continuing.”

Another group within Syriza, called Communist Tendency, on Saturday described the Eurogroup deal as “submission to the blackmail of the troika” and called on lawmakers to oppose it in Parliament.

Sofia Sakorafa, another member of the European Parliament for Syriza, wrote on her Twitter account on Sunday, “The people gave a mandate for the memorandum to be annulled” and “we have no political justification to do the opposite.”