CAIRO >> Egypt has banned the son of U.S. Transportation Secretary Ray LaHood and a number of other Americans from leaving the country as tensions rise over moves by Egyptian authorities to restrict the work of international rights organizations.

The State Department’s top human right official, Michael Posner, told reporters in Cairo that the apparent campaign against pro-democracy groups raised concerns about Egypt’s transition to democracy after Hosni Mubarak’s ouster and warned it could affect future assistance to Egypt, one of the largest recipients of U.S. aid.

Sam LaHood, who heads the International Republican Institute in Egypt, was recently kept from boarding a flight out of Egypt. LaHood’s father, a former congressman from Illinois, is transportation secretary and the most prominent Republican in President Barack Obama’s administration.

The IRI was one of 10 organizations raided last month by Egyptian security forces, who carried off computers and boxes of files and interrogated staff members. The U.S. and the U.N. denounced the raids, but the Egypt defended them as part of a legitimate investigation into whether the groups were operating legally in Egypt.

Posner, who was in Cairo as part of a regional tour, did not give specifics about the Americans who have been barred from leaving Egypt, but he linked it to cases being investigated by Egyptian courts.

He spoke of the "difficult environment" for non-governmental organizations in Egypt and called on authorities to "redress this situation."

"All need to have the ability to operate freely, not constrained by the content of their work," he said.

Posner also pointed to recent U.S. legislation requiring Egypt to verify certain benchmarks during its transition to democracy in order to continue to receive American aid.

The future of American aid to Egypt has come under greater scrutiny since Mubarak was forced out of power on Feb. 11 after 18-days of mass protests last year. A council of top generals has ruled the country since, and the country’s first elected parliament since the uprising was seated this week. Its domination by Islamists has raised concerns in some circles that the new government could seek changes in Egypt’s peace treaty with Israel.

Posner said that antidemocratic moves inside the country could affect aid as well.

"Obviously, any action that creates tension between our governments makes the whole package more difficult," he said.

It remains unclear how many Americans or other non-Egyptians are on the list.

Lisa Hughes, country director of the Egypt office of the National Democratic Institute, said Egyptian authorities have said that six staffers at her organization are on the list, three Americans and three Serbs.

Hughes, who is on the list, was planning fly home to the U.S. next month, she said. Her organization was also raided in December.

"I think we would be silly not to be concerned," she said. "We were concerned the moment armed men showed up at our office door, and this has done nothing to calm those concerns."