Greece's new conservative prime minister Kyriakos Mitsotakis was sworn in Monday after a sweeping election victory put him in charge of the EU's most indebted member with promises to end a decade of economic crisis.
"The Greek people gave us a strong mandate to change Greece. We will honour it to the full," the 51-year-old Harvard graduate and former McKinsey consultant said after taking his oath of office in a televised ceremony, his wife and three children close by.
"Hard work begins today. I am completely confident that we will prove equal to the challenge."
A new cabinet will be sworn in on Tuesday and meet on Wednesday, he said.
Outgoing European Commission chief Jean-Claude Juncker and Turkish president Recep Tayyip Erdogan were the first to congratulate Mitsotakis on Sunday.
On Monday, Russian president Vladimir Putin cabled in, and a spokesman for German chancellor Angela Merkel said Berlin looked forward to working with the new Greek leader.
Merkel also thanked outgoing leftist PM Alexis Tsipras for his cooperation "with mutual confidence and trust during very demanding years," the German spokesman said.
The US-educated conservative faces a hefty challenge as he takes over from Tsipras, who imposed austerity measures required under a bailout to keep Greece in the eurozone.
The country's public debt last year stood at 335 billion euros ($376 billion), or 180 percent of GDP.
The debt load is forecast to fall to 168 percent of GDP this year, but only under belt-tightening brought in under Tsipras's Syriza party -- something Mitsotakis's New Democracy party says is stifling growth.
The tricky job of keeping Greece's international creditors onside while easing the hardship on Greeks -- by lowering taxes and renegotiating fiscal targets -- could result in a short honeymoon phase for Mitsotakis.
A Eurogroup finance meeting on Monday will discuss the state of Greece's economy after tax cuts rolled out by Tsipras in a last-ditch attempt to win over voters.
'Message for change'
Former banker Mitsotakis has pledged to create jobs and "steamroll" obstacles to business.
Those pledges wooed Greek voters, who handed him nearly 40 percent of the vote in Sunday's election, well ahead of the 31.5 percent given to Tsipras.
"It's a strong message for change in Greece," Mitsotakis told reporters on Sunday.
Last week he told AFP his mission was "to make sure we restart the economy" with "ambitious growth driven by private investments, exports and innovation".
He predicted he could persuade Greece's creditors to accept the easing of tight fiscal targets with "a comprehensive reforms package".
Tsipras, for his part, warned that Mitsotakis would do away with the social spending he brought in to help Greece's vulnerable groups.
He portrayed the Mitsotakis family -- one of Greece's leading political dynasties -- as part of a failed system that bankrupted the country in 2010.
Son of a PM
Mitsotakis is the son of former prime minister Constantine Mitsotakis, one of the country's longest-serving parliamentarians. His sister Dora Bakoyannis is a former minister and Athens's first female mayor.
And in a first even for a country accustomed to family links in politics, the recently-elected mayor of Athens is the incoming prime minister’s nephew.
Mitsotakis took charge of New Democracy three years ago. Following the election, his party will have a majority of 158 seats in the 300-member parliament.
New Democracy was last in power in 2014, in coalition with the Greek socialists.
Syriza's parliamentary presence will shrink from 144 seats to 86. Tsipras has promised to remain an "active" voice in opposition in defence of labour rights.
Sunday's election was Greece's third in as many months.
In May, New Democracy beat Syriza by nearly 9.5 points in European parliament elections. A week later, it completed a near-sweep of Greek regions in local elections. After that, Tsipras was forced to call an early general vote.
Entering parliament for the first time are Greek Solution, a nationalist party formed by TV salesman Kyriakos Velopoulos, and MeRA25, an anti-austerity party founded by maverick economist and Tsipras' former finance minister Yanis Varoufakis.
Neo-Nazi party Golden Dawn was shut out of parliament for the first time since 2012.
Golden Dawn, until recently Greece's third-ranking party, is in steep decline amid an ongoing trial for the 2013 murder of an anti-fascist rapper, allegedly carried out with the knowledge of senior Golden Dawn members.