Egyptian Justice Minister Abdel Abdel-Hamid rejected a letter Tuesday from U.S. Ambassador Anne Patterson asking him to” review a travel ban imposed on Americans. At least six U.S. citizens have taken refuge in the American Embassy in Cairo to ensure their safety.

State Department spokesman Mark Toner confirmed at a briefing in Washington that the letter had indeed been returned. He added that the U.S. was continuing talks with Egypt over the restrictions that have trapped a group of American citizens in the country for more than a month.

The Americans all work for either the International Republican Institute (IRI) and/or the National Democratic Institute (NDI), both of which receive funding from the United States. The organizations were among 17 pro-democracy nonprofit groups raided — and in many cases, shut down — in January by the Egyptian government.

Six have been arrested and charged by an Egyptian judge with working for and receiving salaries from an unregistered non-governmental organization (NGO), including Sam LaHood, son of U.S. Transportation Secretary Ray LaHood. The group could be placed on trial and sentenced to up to five years in prison, LaHood said over the weekend. He personally was stopped from leaving the country last Saturday.

Abdel-Hamid told Egypt’s new parliament — which is now controlled by the once-outlawed Islamist Muslim Brotherhood’s Freedom and Justice and Salafi Al-Nour parties — that he had told the U.S. Embassy the letter had come from the wrong person, and was addressed to the wrong person. The Egyptian minister said the letter should have been written by those being investigated, and should have been addressed to the investigating judges, the Associated Press reported.