Iceland's co-coach Heimir Hallgrimsson says French swimmer Yannick Agnel's promise to swim around the Nordic island if the minnows win Euro 2016 would be chilly business.

France's Olympic 200m freestyle champion joked on Twitter that he will swim around Iceland -- a distance of 2,008km (1,247mi) -- if Hallgrimsson's side win the European Championship finals.

Having stunned England with a 2-1 shock victory in the last 16, Iceland now turn their sights on hosts France for a place in the semi-finals.

They face the French in Paris on Sunday in the quarter-finals and another upset result would take Agnel a step closer to his chilly mammoth dip.

Hallgrimsson, who combines his role as co-coach alongside Lars Lagerback with his job as a dentist in Iceland, could only smile when asked about the Frenchman's promise.

"I wouldn't recommend it, but that is possible, although he'll have to pick the right weather," said the Iceland coach drily.

Euro 2016 fever has gripped the tiny North Atlantic nation and 10 percent of their 330,000 population is in France supporting their team.

With swelling numbers of Iceland fans set to descend on Paris for Sunday's match at the Stade de France, some media have dubbed it 'the continuing Viking invasion'.

The last time Vikings came to Paris, France's modern-day capital was held under siege from 885-886 after Nordic warriors sailed up the Seine.

Hallgrimsson says Sunday's next invasion of Paris by Nordic football fans promises to be a much more peaceful affair, when asked by a French reporter.

"I have to be honest, I know nothing about the Viking invasion of Paris, it couldn't have been many of them and maybe they were Swedish," he said with a grin -- looking directly at Iceland's Swedish co-coach Lagerback.

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