European stock markets slid at the start of trading on Monday after eurozone member Greece rejected creditors' austerity demands in a weekend referendum.

Frankfurt's DAX 30 shed 2.11 percent to 10,825.06 points and the CAC 40 in Paris fell 2.06 percent to 4,709.01 points. Outside the eurozone, the FTSE 100 index lost 1.07 percent to stand at 6,515.67 compared with Friday's close.

French President Francois Hollande and German Chancellor Angela Merkel said Monday the door was open for a return to debt negotiations with Greece, but called on Athens to make "serious" proposals.

"The door is open to discussions and it is now up to the government of Alexis Tsipras to make serious, credible proposals so that this willingness to stay in the eurozone can translate into a lasting program," Hollande said.  

Greek Prime Minister Alexis Tspiras has "torn down the bridges" between Greece and Europe and new negotiations are "difficult to imagine" after the apparent 'No' vote in the Greek referendum, German deputy chancellor Sigmar Gabriel said on Sunday.

Tsipras and his government are taking Greece down a path of "bitter renunciation and hopelessness," Gabriel told the Tagesspiegel newspaper in the first high-level reaction from the German government.

Greece has moved a step closer towards a eurozone exit, Russia's deputy economy minister said Sunday, as early results from a crucial bailout referendum suggested Greeks had overwhelmingly rejected creditors' demands for more austerity.

"You can't fail to understand" that this means "a step towards an exit from the eurozone", Alexei Likhachev was quoted as saying by the state TASS news agency.

Greece will have to introduce another currency if it votes 'No' in Sunday's referendum on its potential bailout terms, European Parliament president Martin Schulz said on German radio.

He told Deutschlandfunk that, in the event of a 'No' result, Greece would "have to introduce some other currency because the euro is not available as a means of payment."

Hamas authorities on Sunday reopened the offices of the Gaza Strip's only mobile telephone company, five days after closing them on accusations of tax-dodging.

A statement from attorney general Ismail Jaber's office said that he had "ordered the reopening" of telecom provider Jawwal in Gaza City, but it did not give reasons.

Greece's government on Sunday looked to have won a 'No' it had been seeking in a referendum on bailout terms, but the euro immediately plummeted on fears the result could splinter the eurozone.

An official tally of over half the ballots cast showed a resounding 61 percent of Greek voters had backed the government's 'No' in the plebiscite. 

Tourists are vital to Barcelona's economy, but the 27 million people who visit each year have become a headache for the new mayor as she battles to save the iconic Spanish Mediterranean port from becoming a bland theme park.

"Tourists go home" is frequently found painted on the walls of buildings in the center of Spain's second-largest city, which is struggling to cope with a surge in tourism that started when it hosted the Olympics in 1992.

In the five months since he came to power vowing to deliver his country from years of biting austerity, Prime Minister Alexis Tsipras has kept Greece and Europe guessing.

For some he is a master strategist who has called the bluff of Greece's creditors by giving the people the final say on a painful debt deal.

German Chancellor Angela Merkel and other EU leaders await with trepidation the outcome of a referendum in Greece Sunday that is already dividing opinion in Europe and could even shape its future.

After months of fruitless talks with its creditors, Greece's dramatic bid to place a bailout decision in the hands of its people will have an impact far beyond the heavily-indebted country's borders, analysts warn.