ATHENS, Greece — Banks and ATMs were shut throughout Greece today, the first day of capital controls announced by the government in a dramatic twist in the country’s five-year financial saga.

Despite the closures, pensioners lined up just after dawn at bank branches hoping they would be able to receive their pensions, which were due to be paid today. The finance ministry said the manner in which pensions would be disbursed would be announced this afternoon.

The bank closures came after Greeks rushed to ATMs over the weekend to withdraw money following Prime Minister Alexis Tsipras’ surprise call for a referendum on creditor proposals for the reforms Greece should take to gain access to blocked bailout funds.

The referendum has been set for Sunday.

The capital controls are meant to staunch the flow of money out of Greek banks and spur the country’s creditors to offer concessions before Greece’s international bailout program expires Tuesday.

Once that happens, Greece loses access to the remaining 7.2 billion euros ($8.1 billion) of rescue loans, and is unlikely to be able to meet a 1.6 billion-euro debt repayment to the International Monetary Fund due the same day.

The crisis has thrown into question Greece’s financial future and continued membership in the 19-nation shared euro currency — and even the European Union.

The European Union’s executive Commission, which enforces the bloc’s laws, said the imposition of capital controls was “prima facie, justified.”