Egyptian police have released an activist with Egyptian and German citizenship who was arrested after he took part in a march supporting Palestinians in the Gaza Strip.
Christian and other friends and fellow civil rights and justice activists had organised vigils and petitions across the world. Thousands joined a Facebook group supporting Rizk's cause.
Egypt's State Security Service never explained why 26-year-old Philip Rizk was detained last week.
However, his arrest came as Egypt was feeling sensitive to criticism that it did not do enough to help Palestinians in Gaza during the recent Israeli offensive against the coastal strip's Hamas rulers.
Christian friends and fellow civil rights and justice activists had organised vigils and petitions across the world. Thousands joined a Facebook group supporting Rizk's cause.
Rizk had written in a blog about the situation in Gaza, in which he criticized the Egyptian government's refusal to open its border crossing with Gaza during the 3-week-long offensive.
The activist, a graduate student at the American University in Cairo, also spent two years in Gaza and produced a documentary there about daily life in the impoverished strip.
His sister, Jeanette Rizk, said her brother returned to his family's home in a suburb outside of Cairo after being released before dawn on Wednesday 11 February 2009. Police also confirmed his release.
"I can confirm now at this time that he is free," she told Associated Press, the BBC and other agencies.
Mr Rizk was detained on Friday by plainclothes Egyptian State Security officers during a pro-Gaza rally north of Cairo.
The German Foreign Ministry pressed Egypt several times about the case. Students and fellow activists held rallies around Cairo demanding his release.