US president Barack Obama has called for Greece to be offered debt relief during his visit to Athens.

"To the rest of Europe I will continue to emphasise our view that austerity alone cannot deliver prosperity," he said following a meeting with Greek PM Alexis Tsipras.

"I will continue to urge creditors to put Greece on a path of a durable economic recovery.

"Our argument has always been that when the economy contracts this fast, when unemployment is this high, that there also has to be a growth agenda to go with it and it is very difficult to imagine the kind of growth strategy that’s needed without some debt relief mechanism," he continued.

Meanwhile, Leftist groups protesting against the US President's visit clashed with police overnight.

Police used teargas to disperse crowds who tried to break through cordons - petrol bombs were also thrown according to reports from Reuters.

Crowds of up to 7,000 took to the streets close to the Greek presidential mansion where Mr Obama attended a banquet - some carried banners which said 'Unwanted' and US flags were set on fire.

No injuries or arrests have been reported.

Pablo Martinez Monsivais AP/Press Association Images

Speaking in Greece, US President Obama also offered new reflections on the success of US President-elect, Donald Trump:

"You've seen some of the rhetoric among Republican elected officials and activists and media. Some of it pretty troubling and not necessarily connected to facts, but being used effectively to mobilise people," he told a press conference.

"And obviously, President-elect Trump tapped into that particular strain within the Republican Party and then was able to broaden that enough and get enough votes to win the election," Mr Obama added.