Greek debt crisis casts shadow over G7 summit in Germany

Flaring tensions between Greece and its creditors were set to dominate a G7 summit in Germany Sunday, amid fears the debt-wracked country could crash out of the euro and rock the world economy. German Chancellor Angela Merkel, a champion of tough eurozone reform and austerity, will host the other leaders of the Group of Seven industrialised democracies -- the United States, Britain, France, Italy, Canada and Japan. US President Barack Obama arrived in southern Germany early Sunday for the summit