CAIRO, Egypt, AP -The third-place finisher in Egypt’s presidential elections last year was arrested Saturday after his supporters clashed with a rival faction of his political party in a fight over the party headquarters.

The 10-hour clash was part of a leadership dispute that began after Noaman Gomaa came third in Egypt’s presidential elections in September, a worse-than-expected showing that prompted some members of his Wafd party to try to replace him. Gomaa’s arrest means both the leading candidates who ran against President Hosni Mubarak in September elections — Egypt’s first open to multiple candidates — are in custody.

The clashes began after Gomaa and his supporters took control of the party headquarters, then opened fire on supporters of the rival faction who tried to break in, police said. Twenty-three people were injured, and Gomaa was detained along with two other party members and four bodyguards.

The infighting underlined the deepening deterioration of Egypt’s secular opposition parties. The fundamentalist Muslim Brotherhood movement has taken the helm in leading the opposition to Mubarak’s ruling party.

The second-place finisher in the presidential election, Ayman Nour of the Ghad party, is serving a five-year prison term for forgery, charges he said were trumped up to eliminate him from politics.

Mubarak touted the multi-candidate presidential election as the centerpiece of a new campaign of democratic reform in Egypt, a top U.S. ally that he has ruled since 1981.

Critics, however, say reform has ground to a halt. The presidential vote was followed by legislative elections in November and December that saw widespread violence, a miserable showing by secular opposition parties and the rise of the Muslim Brotherhood, which increased its presence in parliament more than sixfold to 88 out of 454 seats.