Obama warns of 'uncontrolled spiralling' over euro debt

US President Obama has warned of an "uncontrolled spiral" if the euro zone countries were allowed to default on their debt.

The US president made his comments during a news conference with Angela Merkel, marking the German leader's first state visit to Washington.

Mr Obama called Greece's debt "significant" and said the country must make structural reforms for its economy to be more competitive in attracting foreign investment.