A 5.2 magnitude earthquake has hit 72 miles (126km) off the coast of the Greek island of Rhodes, the US Geological Survey has said.
The quake struck at a depth of 88 miles (142km). There were no immediate reports of damage.
The Greek government will decide next week when the Athens stock exchange will reopen, after a four-week break required when capital controls were imposed last month, an official said on Thursday.
Athex has been closed since 29 June, when Greece shut its banks and imposed capital controls to ward of a collapse of its banking system after the country rejected a cash-for-reforms deal in its referendum.
The banks reopened on Monday after the country reluctantly struck a deal to receive emergency ECB funding and a bridge loan from the EU.
The official also confirmed that talks with Greece's international creditors on a third bailout would start in Athens on Friday and that the government wants the talks to be concluded by late August.
Greek MPs have overwhelmingly approved a new batch of reforms demanded by the country's international creditors in return for a third multibillion-euro bailout.
The vote followed a whirlwind debate that ended at 4am local time.
Prime Minister Alexis Tsipras once again suffered a revolt in his own radical left party, but had no trouble passing the draft legislation with the backing of pro-European opposition parties.
The reforms were the final prerequisite before Greece can start negotiations with creditors on a third bailout worth around 85 billion euro (£59.5 billion).
Government spokeswoman Olga Gerovasili conceded there is a clear rift within Syriza, but would not say whether rebels would be expelled.
"From this point on, party procedures will be followed in order to deal with the problem," she said after the vote.
The Greek parliament will vote today on a second set of reforms needed to secure its bailout deal.
If MPs approve the financial and judicial reforms, Greece will be able to forge ahead with negotiations for an €86 billion bailout from its creditors.
Prime Minister Alexis Tsipras rallied his Syriza colleagues earlier this week , saying the Greek people had "pinned their hopes" on staying in the euro.
The vote is expected to pass with the support of opposition parties.
Greece has started the procedure to pay €6.25 billion to European Central Bank and the IMF, according to officials.
Banks have reopened across Greece this morning, after being shut for three weeks.
However, the financial situation is not back to normal for ordinary Greeks. Citizens are able to withdraw €420 a week at once instead of just €60 a day, but this limit will effectively remain the same, while capital controls will also stay in place
The latest chapter in Greece's financial crisis begins today as the country's banks prepare to reopen.
However, capital controls will remain in place following the three-week shutdown although German Chancellor Angela Merkel has called for swift aid talks so Athens could also lift withdrawal limits.
The cautious reopening of the banks, and an increase in value added tax on restaurant food and public transport from Monday, are aimed at restoring trust inside and outside Greece after an aid-for-reforms deal last week averted bankruptcy.
"Capital controls and restrictions on withdrawals will remain in place but we are entering a new stage which we all hope will be one of normality," the head of Greece's banking association Louka Katseli told Skai television.
Greeks will be able to withdraw 420 euros a week at once instead of just 60 euros a day, but the limit will effectively remain the same and capital controls will also stay in place.
"That's not a normal life so we have to negotiate quickly," Merkel said in extracts from an interview with German public broadcaster ARD.
Eurozone finance ministers have agreed to provide a 7 billion euro bridging loan to help Athens meet upcoming debt payments to the European Central Bank (ECB) and International Monetary Fund (IMF).
This loan still needs to be approved by ministers of all 28 EU member states.
The European Central Bank has also said that it will increase emergency support to Greek banks - a first step toward helping the country's banks reopen.
Greek banks will reopen on Monday, a senior banker has told Reuters.
It comes after the European Central Bank decided to increase emergency funding.
Banks have been closed since June 29 after Athens imposed capital controls. "They will open on Monday," the banker said.
The ECB on Thursday increased the cap on emergency funding Greek lenders can draw from the domestic central bank by 900 million euros.