An official at Cairo airport has revealed that a US military plane which arrived to take US NGO workers out of the country was "secured" by a "supreme Egyptian authority."

It is unclear exactly what this means or what this authority is, but it is likely to be either the intelligence service or the presidential guard.

The plane arrived after a decision by Egyptian authorities to lift a travel ban preventing foreign nationals involved in an ongoing NGO case from leaving the country. Earlier, presiding  judges in the case abruptly excused themselves for "reasons of discomfort."

Sixteen of the 43 people facing charges in the NGO trial are US citizens. They are being tried for working in Egypt and raising US funds without appropriate authorisation.

Cairo Airport Authority officials this morning prevented a British man involved in the NGO case from leaving the country.

Among the groups under investigation are the US-government funded National Democratic Institute – founded by former secretary of state Madeleine Albright – and the International Republican Institute, whose chairman is Republican senator John McCain. Both organisations are affiliated with the two major political parties in the United States.

Both the NDI and the IRI receive most of their funding from the US Agency for International Development (USAID), the US State Department, and the National Endowment for Democracy.