A warning statement by the US embassy to its nationals has raised eyebrows The US embassy in Cairo issued a security alert on Saturday warning of "credible information" indicating the possibility of attacks targeting American women engaged in missionary activities, writes Doaa El-Bey. "The embassy has credible information suggesting terrorist interest in targeting US female missionaries in Egypt," read the statement posted on the embassy's website. "Accordingly, US citizens should exercise vigilance, taking necessary precautions to maintain their personal security." The statement also advised US citizens to maintain valid travel documents and register with the embassy so they can be contacted in case of emergency. The statement gave no further details of the source or nature of the "credible information" and did not elaborate on the "missionary activities" in which those targeted are involved. "The embassy received threat information that we were obligated to share with American citizens, whom we expect to abide by local law," the US embassy told Al-Ahram Weekly. Egypt permits missionaries inside its borders as long as they do not attempt to convert Muslims. Their missions are mainly charitable, working among the poorest segments of Egyptian society. One diplomat, speaking on condition of anonymity, said the warning was predictable given the wave of anger that met the YouTube posting of the trailer for the film The Innocence of Muslims, especially given the reported involvement of an Egyptian Copt in its production. Egyptian protesters demonstrated in front of the US embassy in response to the film, invading the embassy grounds and forcing security forces to build a concrete barricade blocking access to the building. That latest security alert comes six weeks after the US embassy warned Americans not to travel to the Sinai Peninsula following an Israeli warning of an imminent terrorist attack. The following day 16 Egyptian border guards were killed in Rafah. The alert appeared on the embassy website a day after Kay Granger, the Republican congresswoman who oversees foreign aid, froze a request by the administration for $450 million in cash for the Egyptian government. Granger said the proposal had come to Congress at a time when US-Egyptian relations are under intense scrutiny. Not convinced the assistance was urgently needed, she opted to put it on hold. The United States provides Egypt with $1.55 billion annually -- $250 million in economic aid and $1.3 billion in military aid. Recently calls have been growing to refuse such funding on the grounds it provides Washington with a tool to influence Egyptian domestic policy. The relationship between the United States and Egypt has been rocky since the overthrow of president Hosni Mubarak. The Egyptian government angered Washington when it cracked down on democracy and human rights groups earlier this year, including three US-funded NGOs. Negative signals proliferate and the prospects of an improvement in relations between the two states are dim, especially if US presidential candidate Mitt Romney wins. He has promised a tougher line with Egypt and stronger relations with Israel.