Egyptian authorities barred a British woman from leaving Egypt on Friday because she is on a list of people under investigation over ties to foreign non-profit groups accused of fomenting unrest in the country, an airport official said. The government’s crackdown on the NGOs has caused one of the most serious rifts in decades between Egypt and its strategic ally, the United States. US officials and legislators have warned it could sever the $1.5 billion in US aid to Egypt, one of the longest and largest in the world. The airport official said the woman was ordered off a London-bound plane in Cairo, but was not arrested. He spoke on condition of anonymity because he was not authorized to talk to the media. The woman joins a list of at least 10 foreigners, including six Americans, who have been barred from travelling as part of the criminal investigation. In London, Foreign Office officials said they had contacted British diplomats in Egypt seeking more information. Egyptian judges have referred 16 Americans, and 27 others, including Europeans and Egyptians, to trial on accusations they illegally used foreign funds to foment unrest in the country. The country’s military rulers have so far stood firm behind the case, and military-backed Prime Minister Kamal Al Janzouri has said Egypt would not “kneel” before pressure to cut the aid. Officials have also used the case to accuse the growing protest movement in Egypt of being a pawn in the hands of the US, which is allegedly seeking to destabilise the country. Youth groups and revolutionary movements that led the popular uprising that pushed former President Hosni Mubarak out of office last year have become increasingly assertive in challenging the military council that replaced him. The generals have promised to hand over power on June 30, but protesters want them to step down immediately. They accuse the military of mismanaging the transition to democracy, and of trying to preserve Mubarak’s regime. On Friday, thousands of protesters organised nearly a dozen marches across Cairo, heading to the Ministry of Defence. “We are not tired. A total revolution or none,” shouted protesters marching toward the ministry. “Down, down with military rule.” The different marches converging on the well-guarded ministry differed from the protesters’ usual tactics, taking them away from rallies at Cairo’s Tahrir Square that was the epicentre of the uprising. Smaller, more symbolic marches to the ministry have been organised before. The rallies come on the eve of the anniversary of Mubarak’s resignation on February 11, 2011. The protesters have also called for a rolling general strike to begin Saturday to pressure the military rulers to step down. The generals and the miltary-backed government have been critical of the strike call, casting it as another example of foreign attempts to weaken Egypt. The state media and a Facebook page affiliated with the ruling generals accused the US of using local institutions, such as the American University in Cairo, to agitate for the strike. Religious figures and the powerful Muslim Brotherhood group, which controls nearly 50 per cent of the country’s newly elected parliament, have also condemned the strike, with some saying it further threatened the already dire economic situation.