Egyptian officials said Thursday they would request an inquiry into the lifting of the ban, which covered, among others, Sam LaHood, son of U.S. Secretary of Transportation Ray LaHood.
The Americans who left have promised to return for trial, and the lifting of the travel ban does not clear the non-profit groups and their employees of the spying charges they face, The New York Times reported.
"The Criminal Court decided on Wednesday to cancel the ban in return for a bail of LE2 million [around $331,000] per each defendant," Ahmud Abdel Hafez, attorney for the 19 American defendants, told Gulf News.
Essam Sultan, vice president of the moderate Islamist Wasat Party, said he would request an urgent investigation of the decision.
"Removing this ban violates the law and constitutes a glaring breach of the Egyptian judiciary's independence," he said.
The lift of the travel ban came mere hours after a three-judge panel withdrew from hearing the case due to "a feeling of uneasiness."