Tens of thousands of Greeks have taken to the streets of Athens as the German Chancellor arrives in Athens to signal her strongest support yet for a government struggling to implement fresh austerity cuts.
Police clashed with protestors, firing tear gas at demonstrators throwing stones and petrol bombs in one of the capital's biggest protests in months.
Angela Merkel is the first German chancellor to visit Greece in decades and is making her first trip since the debt crisis began here three years ago.
Deemed highly symbolic, Merkel's seven-hour stay signals the attempt by Europe's most powerful lender to keep its poorest peer, Greece, within the 17-nation eurozone.
Merkel also has a desire to further mend relations with Prime Minister Antonis Samaras, who was among the Chancellor's most outspoken critics at the start of the crisis.
"The stakes are enormous," said George Pagoulatos, professor of European Politics and Economy at Athens University. "It is a seminal moment for Europe."
Demonised for her tough talking, uncompromising stance and widely depicted as the poster girl of fiscal frugality, the German chancellor has received a hostile reception.
More than 7,000 police officers, secret agents, snipers and commandos were deployed across the capital in the biggest security drill since US President Bill Clinton visited Athens after sanctioning Nato-led bombing raids in Kosovo 13 years ago.
A flurry of protests are planned throughout the day. GSEE and ADEDY, the umbrella labour unions for private and public sector employees, have called for a three-hour strike across the greater Athens area from noon, bringing the country's already anaemic economy to a fresh standstill.
Looming budget cuts have uncorked fresh social unrest, with the young, firebrand leader of Greece's main opposition party, Syriza, also calling on workers to flood the streets of Athens to show Merkel "the real Greece".
Late on Monday, police ordered a ban on protest gathering, but opposition parties have defied the decree, urging Greeks to gather at the German embassy.
Since his election in June, Samaras has been struggling to agree with international lenders on a fresh batch of brutal budget cuts.
Failure to clinch a deal on the \$11.5b euro cuts could tripwire a key meeting of European leaders next week, forcing them to block a \$31bn loan instalment to cash-strapped Greece, pushing it to bankruptcy within weeks.
That in turn could imperil the fate of the European currency, which Merkel has built her legacy on, proving invaluable in efforts to keep the eurozone intact.
By signalling her support for Greece to stay in the troubled eurozone, pundits, politicians and skittish market investors expect the visit to nudge the budget talks to a compromise solution, paving the way for Europe's disbursal of vital bailout funds.
Strapped for cash, Athens has said it has enough money to pay pensions and its expenses until the start of November.