France, Germany, Mexico, Brazil have objected to the US surveillance program.
28 leaders have considered the facts and are weighing in on the possibility of espionage among friends and allies.
The US calls it outrage theater and respond that this goes on among countries.
The actual scope of National Security Agency snooping abroad has forced President Obama to listen to complaints from allies who are angry about the surveillance net that has sparked an international debate over the limits of American spying.
There is a growing list of nations besides Brazil, France, Germany and Mexico demanding specific answers from Washington.
The White House appears to be troubled by these exposures based on leaks from intelligence contractor Edward Snowden.
They have said that is not now listening in on allies like Germany, but have not denied the possibility that communications may have been intercepted in the past.