The Eurogroup of euro zone finance ministers will hold a conference call early on Wednesday.
Getting the Greeks to say no was the easy part. Now Tsipras must quickly mend fences with his European partners.
The outgoing finance minister gambled that the Europeans would not risk a Greek exit from the eurozone. He got that badly wrong.
In the EU, there is supposed to be no turning back, but what happens when a country can't keep up?
Latvia, Ireland, Spain, Portugal and Slovakia endured austerity and are in no mood to allow Greece off the hook.
Varoufakis had campaigned for Sunday's sweeping 'No' vote, accusing Greece' creditors of "terrorism".
The day before a historic vote, the country is torn between supporters and dissenters of the referendum.
The protests laid bare the deep divide heading into a referendum that may decide the country's future in Europe's single currency.
Tsipras said negotiations would continue for a better deal with international creditors after the vote.
The poll put the 'Yes' camp on 44.8 percent against 43.4 percent for the 'No' vote.
Due to overwhelming interest, the IndieGoGo web page later crashed
Greece needs an extra 50 billion euros over the next three years and significant debt relief to stay afloat, its creditors warned Thursday.
Less than 24 hours after he wrote a conciliatory letter to creditors asking for a new bailout, Tsipras abruptly switched back into combative mode.
Greece has overtaken Italy as the main entry point for those seeking refuge or a better life in Europe.
Greek PM Tsipras says a 'no' vote would step up pressure on creditors to give the country an economically viable agreement.
The Greek prime minister made concessions on major sticking points in a letter to eurozone ministers.
Agents are contacting major clubs to discuss what will happen the event of a Greek default.
Greece owes official lenders 242.8 billion euros ($271 billion).