This weekend, there were long lines at automated teller machines across Greece after Greek Prime Minister Alexis Tsipras called for a referendum late Friday night to be held on July 5 to address an ultimatum from its European creditors. Reuters reported that the lines on Saturday were so long that more than one-third of the ATMs ran out of euros and had to be replenished, a process that can take a couple of hours. In an effort to prevent further capital outflows and deposit withdrawals the Greek banks will reportedly be closed "from Monday." To give you an idea of the situation, check out these photos of ATM queues being shared on Twitter: Athens, Metro. Not tickets. ATM's #greferendum pic.twitter.com/QpHKDUrGsp — Vasilis Dalianis (@VasilisDalianis) June 28, 2015 Happening now at Zofria(Greece) #dimopsifisma #Greferendum #ATM pic.twitter.com/2Y76E6IykE — 24 Hours Europe (@24heuropegr) June 28, 2015 This ia an ATM queue in the centre of Athens now #Greece #Greferendum pic.twitter.com/lx12DYnJIW — Loukia Gyftopoulou (@loukia_g) June 28, 2015 My brother sends me this pic of ATM lines in Greece, many have run out of cash already. pic.twitter.com/tceblU28ZS — Andrea Tantaros (@AndreaTantaros) June 27, 2015 People stand in queue to use ATM machines at bank in Thessaloniki on June 27 http://t.co/ECdZvEElG6 #bankrun #Greece pic.twitter.com/hkjNJNRSvg — Ian Fleming (@SchweizerGeld) June 27, 2015 An ATM screen in Greece pic.twitter.com/YLqhvlZsiE — Corey Hutchins (@CoreyHutchins) June 27, 2015 Queue for an ATM in Greece. People wanting physical Euros. Most ATMs are empty now. pic.twitter.com/iKW6EvHGGC — Jason Hunter (@hunterhacker) June 27, 2015 Greeks in Kalamata lining up at an ATM. All over Greece ppl are running on the banks! #Greece https://t.co/wn9idJ2vCk pic.twitter.com/aWJp7PCmx7 — David Kwong (@davidkwong) June 27, 2015 No good sign: a queue even at the ATM inside the Athens parliament. #Greece pic.twitter.com/ObZUVDiRxZ — Zacharias Zacharakis (@zacys) June 27, 2015 An interesting time to be in #Greece. #ATM #Artemida #Greferendum #ATMlineup #EU #euro2015kg pic.twitter.com/wflwWgZL6c — Ashley Smith (@Ashley_Realtor) June 27, 2015 #Greece atm This morning in small town 10 munutes later ATM run out of money pic.twitter.com/Bq3gc5TOCz — jaksa scekic (@jaksa007) June 27, 2015 Awkward: Longest ATM line I saw in #Athens today was inside #Greece parliament #greferendum #bankrun w/ @JimBYardley pic.twitter.com/35qMfGqDI8 — Dimitris Bounias (@DimitrisBounias) June 27, 2015 SEE ALSO: Greek banks will be closed on Monday Join the conversation about this story » NOW WATCH: How one simple mistake cost 'Real Housewives' superstar Bethenny Frankel millions