Obama, whose political prospects have suffered from persistently high unemployment and ballooning US debt, has pinpointed the euro zone crisis as one foreign "headwind" hitting the US economy.

After a meeting with German Chancellor Angela Merkel, he stressed the importance of German "leadership" on the issue -- a hint that he expects Berlin to help -- while expressing sympathy for the political difficulties European Union countries face in helping a struggling member state.

A proposal for a second Greek bailout package worth EUR80 billion to EUR100 billion over three years was taking shape, euro zone sources said.

Merkel, under political pressure at home to avoid being the financial savior for other struggling European countries, said Germany understood its role.

With US unemployment at 9.1 percent, Obama has blamed outside forces for impeding the economy, including high fuel prices, the earthquake in Japan and the euro zone crisis.

Obama said Greece had to make structural reforms and instill greater transparency in its economy.

But his main message was aimed at EU countries -- and, by default, wealthy Germany -- to step up to help Athens.

The euro debt problems dominated discussions between Merkel and Obama, who also touched on foreign policy issues such as the wars in Afghanistan and Libya.

Obama welcomed Merkel at a formal ceremony on the White House lawn with firing cannons and military musicians adding to the pomp of an official visit.

Later in the evening Obama and his wife Michelle hosted Merkel and her husband, Joachim Sauer, for a state dinner, where the president awarded her the "Medal of Freedom" -- the highest U.S. civilian honor.

Obama noted the event, held open-air in the Rose Garden to take advantage of a warm Washington evening, was the first such state dinner of his presidency for a European leader.