Just hours before a high-profile ceremony, the United States Friday canceled an award to an Egyptian activist.

Just hours before a high-profile ceremony, the United States Friday canceled an award to an Egyptian activist after learning she had praised the 9/11 attacks and the killing of Israelis.

Samira Ibrahim was to have been honored along with nine other women at the International Women of Courage Award hosted by top US diplomat John Kerry and First Lady Michelle Obama.

But in an embarrassing failure for the State Department's vetting process, it was revealed Ibrahim had sent some anti-American remarks on her prolific Twitter account.

"Upon further review, the department has decided not to present her with the award," State Department spokeswoman Victoria Nuland told journalists.

The annual award marking International Women's Day pays tribute to "exceptional courage and leadership in advocating for women's rights and empowerment, often at great personal risk," according to the State Department.

On Thursday, officials had already decided to postpone the award for Ibrahim after she alleged that her account had been hacked when reports of her tweets emerged.

The rightwing Weekly Standard said Ibrahim had written in August: "An explosion on a bus carrying Israelis in Burgas airport in Bulgaria on the Black Sea. Today is a very sweet day with a lot of very sweet news."

She also allegedly wrote on September 11 "Today is the anniversary of 9/11. May every year come with America burning," the Standard said.

"There were obviously some problems in our review process, and we're going to do some forensics on how that happened," Nuland admitted on Friday.

Ibrahim had been initially chosen "because of the incredible bravery and courage she displayed at the time of the Tahrir Square protests," Nuland had said earlier in the week.

She had been subjected to "real police violence" which she had spoken out against and "she became a real leader in her country in trying to address gender-based violence and other human rights abuses," Nuland added.

Among those being honored are the Indian student who died after being gang-raped in a bus in Delhi in December; Tsering Woeser, a Tibetan poet and blogger; Malalai Bahaduri, a first sergeant and senior instructor with the Afghan National Interdiction Unit, and a Syrian human rights lawyer, Razan Zeitunah.