In a parallel bid to break the dangerous deadlock, the Greek leader also renewed the request to international creditors for an extension of the bailout for a few days.
Tsipras did not clarify whether the banks would remain shut and capital controls would be imposed as of Monday in a bid to deal with an alarming increasing bank run during the weekend amidst fears of a looming credit event, Xinhua quoted the finance ministry sources as saying.
According to the sources, the banks would remain closed for a week and the maximum sum savers will be able to withdraw will be less than 100 euros per day. Official announcements were expected later on Sunday at the end of a cabinet meeting which was underway.
The Leftist leader accused creditors of blackmailing Greek people to accept a harsh draft reforms for cash deal.
He assured that in any case deposits were safe, that pensions and salaries would be paid normally this week and called on Greeks to keep cool.
Tsipras' address was made a few hours after the European Central Bank decided to keep the emergency liquidity assistance flow to the Greek banking system at current levels following Athens' surprise move on Saturday to call a referendum next Sunday.
After the collapse of five month negotiations with international lenders on the terms of post bailout cooperation the Leftist government called voters to accept or reject the draft deal tabled by lenders on Thursday in Brussels.
The step triggered a series of reactions starting with Euro Group's decision on Saturday that the extended second bailout expires on June 30, as the two sides agreed in February, and no further extension would be granted with no deal.
Without an agreement on June 30, Greece was unlikely to make the delayed loan installment to International Monetary Fund.
"Yesterday's Eurogroup's decision to reject the request for a short extension of the programme was an unprecedented for European standards act which puts in question the right of a sovereign people to democratically decide," Tsipras said.
"The subsequent decision of the European Central Bank today to limit the liquidity available to the Greek banks and forced the central Bank of Greece to recommend a bank holiday and the imposition of capital controls," he added.
He accused creditors of trying to obstruct the referendum process and appeared confident that they will fail and that Greek people will dismiss ultimatums.
Tsipras talked about a great insult for the democratic tradition of Europe and added that Athens expected even tonight that institutions would reverse the Euro Group's denial for an extension to the bailout to allow voters to choose with no pressure on July 5.
"Greeks' dignity versus blackmails and injustice will send a message of hope and pride across Europe," he said.