Egypt’s election commission on Tuesday disqualified an ex-premier from running for president, The Associated Press reported.

Ahmed Shafiq, who was former President Hosni Mubarak’s prime minister during the 18-day uprising last year, was disqualified because of a law, passed on Monday, that bans senior officials from the Mubarak regime from running for office.

The disqualification is the latest twist in an already turbulent process aimed at replacing Mubarak. The commission has already nixed 10 other candidates on technical grounds, including three of the front-runners.

The law, which was approved Monday by Egypt’s military rulers after being passed by the Islamist-dominated parliament, bans senior Mubarak-era officials who served in the past 10 years from running for office.

The law was aimed at Shafiq as well as at Omar Suleiman, who was Mubarak’s longtime spy chief and was named vice president at the end of his reign. Suleiman, however, had already been disqualified on other grounds before the law was ratified.

Along with Suleiman, the commission disqualified ultraconservative Islamist Hazem Abu Ismail and Muslim Brotherhood chief strategist Khairat el-Shater. The Brotherhood, which clinched the majority in recent parliamentary elections, has announced a backup candidate, Mohammed Morsi. The first round of voting is set for May 23-24.

AP reported that before the decision, Shafiq’s campaign issued a statement calling the new law “a shame and a constitutional sin” that will cast a shadow over the elections because it targets individuals.

With the decision to disqualify Shafiq, the leading non-Islamist candidate is now Amr Moussa, who served as Egypt’s foreign minister under Mubarak and in 2001 moved over to head the Arab League.

Earlier this week, Moussa said Egypt is facing daunting challenges and presented his decades as a senior government official as a prime reason to vote for him and not an Islamist.