CAIRO – Egyptian Vice President Mahmoud Mekki announced his resignation Saturday, the day of a referendum on a new constitution that leaves unclear whether his position would be maintained. In a statement, Mekki said he was stepping down because “political work does not suit my professional character as a judge.” He said he had initially submitted his resignation on Nov. 7, but delayed it until now because of a series of events, including the Israel-Hamas war in Gaza and a decision by President Mohamed Morsi last month to bolster his own powers. “I saw that today (Saturday) was an appropriate time to announce my resignation as vice president of the republic, and I will continue to volunteer as a soldier,” he said. Mekki, 58, was a respected judge before Morsi named him to the vice presidency in August. He led judicial opposition to ousted leader Hosni Mubarak, but eschewed calls to become a presidential candidate himself, saying he wished to stay politically independent. Mekki had previously intimated to Egyptian media that he considered resigning. His brother, Ahmed Mekki, is Morsi's justice minister. Mahmoud Mekki was only the second Egyptian vice president in more than 30 years. Mubarak never filled the post during his three-decade tenure, until he named his intelligence chief, Omar Suleiman, to the job in February 2011, in the midst of the revolt that eventually toppled him. Meanwhile, Egyptians voted Saturday in the final round of the referendum on a new constitution championed by Morsi and his Islamist allies, but with little prospect of the result quelling fierce protests. On the eve of polling, clashes in Egypt's second city Alexandria injured 62 people as stone-throwing mobs torched vehicles, underlining the turmoil gripping the Arab world's most populous nation. Some 250,000 police and soldiers were deployed to provide security during the referendum. The army has also positioned tanks around the presidential palace since early this month. The proposed charter was expected to be adopted after already garnering 57 percent support in the first round of the referendum a week ago. A slim margin and a low first-round turnout in the referendum is expected to embolden the opposition, which looks likely to continue its campaign against Morsi and his Muslim Brotherhood backers. Electoral officials announced they were extending voting by four hours, to 11:00 p.m. (2100 GMT), as they did in the first round. Egyptian human rights groups alleged the first round was marred by fraud, setting up a possible later challenge to the results. They called news conferences for Sunday to give their observations of the second round of polling. Preliminary tallies from the final round were expected early Sunday. Full official results will be released “two days after the end of polling,” the electoral commission said. – Agencies