German Chancellor Angela Merkel has pledged her country's continuing support to Greece, during her first visit to Athens since the eurozone crisis erupted nearly three years ago.
Mrs Merkel said Greece had made good progress in dealing with its vast debt but that it was on a "difficult path".
Thousands of people who blame Germany for forcing painful austerity measures on Greece are protesting in Athens.
Tuesday morning: There is tight security in Athens ahead a visit by German Chancellor Angela Merkel, her first since the eurozone crisis erupted nearly three years ago.
Some 7,000 police officers are on duty, public gatherings are banned in certain areas of the city and protesters have been warned to "protect the peace".
The visit comes as Greece bids to pass new cuts of 13bn euros (£10.5bn; $17bn) to qualify for more bailout cash.
Analysts say Mrs Merkel is regarded by many Greeks as the author of austerity.
While Germany has contributed the most money in the bailing out of Greece, the BBC Europe editor Gavin Hewitt says its chancellor is held responsible for demanding that Greece make swingeing cuts in exchange for the financing it has received.
Speaking on Monday, Jean-Claude Juncker, chairman of the Eurogroup finance ministers of the eurozone, raised the pressure on Greece, calling on the government to demonstrate it could implement planned reforms "by 18 October at the latest" to qualify for the next bailout instalment of 31.5bn euros.
He was speaking as the eurozone's new permanent fund to bail out struggling economies and banks was formally launched at the finance ministers' meeting.
There has been growing unrest in Greece at the planned new cutbacks.
Police have banned protests on Tuesday in much of central Athens, and within a 100-metre (110-yard) radius of the route Mrs Merkel's motorcade will travel - although two planned protests elsewhere in the city will go ahead.
On Monday, public order minister Nikos Dendias appealed to protesters to "protect the peace, and above all our country's prospects and our international image", Reuters news agency reported.
Mrs Merkel will be in Athens for about six hours, and will have talks with Greek Prime Minister Antonis Samaras.
The meeting is a gamble, our correspondent says.
If there is chaos on the streets, it will only underline for the German public that Greece is a lost cause.
But Mrs Merkel's visit - her first to Greece in five years - is sending a symbolic message that she wants Greece to stay in the eurozone, our correspondent adds.
Meanwhile, the International Monetary Fund said on Monday that the global economic recovery was weakening, with government policies having failed to restore confidence.
It added that the risk of further deterioration in the economic outlook was "considerable" and had increased.
Source: BBC News