Updated

The Obama administration pulled back on plans to give an award to an Egyptian activist after anti-American and anti-Semitic messages were discovered on her Twitter account.

Samira Ibrahim, an Egyptian activist who rallied worldwide attention against forced "virginity tests" on female protesters, was supposed to be honored Friday along with nine others by first lady Michelle Obama and Secretary of State John Kerry. The State Department, though, announced that it would postpone the International Women of Courage award while officials investigate the tweets. Ibrahim is now headed back home.

"We, as a department, became aware very late in the process about Samira Ibrahim's alleged public comments," State Department spokeswoman Victoria Nuland told reporters.

Ibrahim, who was in the U.S. when the controversy arose, claimed her account was hacked, though the comments stretch back several months. Nuland said the activist has "categorically denied authorship."

But the administration is conducting its own review.

In July of last year, after five Israeli tourists and a Bulgarian bus driver were killed in a bombing, a tweet on her account said: "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."

As a mob was attacking the United States embassy in Cairo on Sept. 11 of last year, pulling down the American flag and raising the flag of Al Qaeda, a tweet on her account said: "Today is the anniversary of 9/11. May every year come with America burning." The tweet was deleted a couple of hours later, but not before a screen shot was saved by an Egyptian activist.

In other posts, she declared Saudi Arabia's royal family "dirtier than Jews" and attributed all crimes against society to Jews and referenced Adolf Hitler.

The tweets were first reported by The Weekly Standard.

Sen. Mark Kirk urged the State Department to investigate and said other women were more deserving of the honor.

In a letter to Kerry, the Illinois Republican said Ibrahim used her Twitter account to "express anti-Semitic views and support for international terrorism" and called her hacking claim "dubious" given the timing and duration of the tweets.

Ibrahim was among seven women subjected to forced "virginity tests" after being detained during a protest in Cairo's Tahrir Square in March 2011.

She helped bring worldwide attention to the tests, which prompted the military to forbid the practice last year.

"Not only did she speak out about that, but she also became a real leader in her country in trying to address gender-based violence and other human rights abuses," Nuland said. "So it was on that basis that she was initially selected."

The State Department said Ibrahim also was arrested in high school "for writing a paper that criticized Arab leaders' insincere support of the Palestinian cause." She is a coordinator of the Know Your Rights movement, which seeks to raise political awareness and advocate women's rights in Upper Egypt.

The Associated Press contributed to this report.