The son of a senior US cabinet minister is among several foreigners working for civil society groups who have been banned from leaving Egypt.
Sam LaHood, the son of Transport Secretary Ray LaHood, was stopped as he tried to board a flight leaving the country.
His organisation, International Republican Institute (IRI), was one of 17 recently raided by authorities.
IRI is a US-funded non-profit that encourages democratic governance.
Egypt’s military government has vowed to investigate how pro-democracy and human rights organisations are funded, and has said repeatedly it will not tolerate foreign interference in the country’s affairs.
In a raid in late December, Egyptian officials confiscated documents and computers at the non-government organisations (NGOs).
Mr LaHood found himself stopped from leaving Egypt when an official stopped him from boarding a plane in Cairo on Saturday, reports said.
“I asked her why I was denied, she said she didn’t know. I asked how to fix it, and she said she didn’t know,” Mr LaHood, 36 told the Associated Press. He was later given back his passport and left the airport.
“The reality is, this is bigger than me or IRI,” Sam LaHood told the Washington Post. “There are 300 NGOs being investigated by the Egyptian government, and only a handful of them are American.”
‘Redress this situation’
The top human rights official at the US state department, Michael Posner, said the move raised concerns about the country’s transition to democracy after the toppling of Hosni Mubarak in February 2011.
Mr Posner warned it could affect future aid, and called on Egyptian authorities to “redress this situation”.
It is unclear how many people are on the list banning them from leaving the country, another NGO official said she believed the restrictions were related to the raids.
Mr LaHood’s counterpart at the National Democratic Institute, Lisa Hughes, said that Egyptian authorities told her six of her staff members – three Americans and three Serbs – were also on the list.
NDI is loosely associated with the Democratic Party in the US and the IRI with the Republican Party. Both are funded through the National Endowment for Democracy.
“I think we would be silly not to be concerned,” Ms Hughes said. “We were concerned the moment armed men showed up at our office door, and this has done nothing to calm those concerns.