Unprecedented Latin American opposition to U.S. sanctions on communist Cuba left President Barack Obama isolated at the Summit of the Americas on Sunday and illustrated Washington's waning influence in the region.

In contrast to the rock-star status he enjoyed at the 2009 summit in Trinidad and Tobago shortly after taking office, Obama has had a bruising time at the two-day meeting in Colombia of some 30 heads of state from across the Americas.

Eleven Secret Service agents and five military personnel were caught in an embarrassing prostitution scandal, Brazil and others have bashed Obama over U.S. monetary policy, and he has been on the defensive over calls to legalize drugs.