Ammon News - * Charter backed by supporters of President Mohamed Morsi but rejected by secular opposition who say it is "too Islamist".
If the constitution is voted down, a new assembly will have to be formed to draft a revised version

CAIRO (Agencies)- Egyptians have started to vote in a referendum on a new draft constitution promoted by its Islamist backers but rejected by the secular and Christian opposition.

Saturday's referendum pits Islamist supporters of President Mohamed Morsi who have clashed with their opponents in Cairo and other cities ahead of the vote seen as a way out of a prolonged political crisis.

Just over half of Egypt's electorate of 51 million will vote in the first round in Cairo and other cities. Polling stations opened at 8am (0600 GMT) and close 12 hours later.

The opposition says the constitution is too Islamist and tramples on minority rights. Morsi's supporters say the charter is needed if progress is to be made towards democracy.

Egypt has been in turmoil nearly two years after the fall of military strongman Hosni Mubarak and Morsi's efforts to return the Arab world's biggest nation to normalcy have been hampered by what the opposition views as his autocratic tendencies.

In Alexandria, where Morsi's Freedom and Justice party is based, tensions boiled over into a street brawl between rival factions armed with clubs, knives and swords.

Several cars were set on fire in Friday's violence and a Muslim preacher who had urged people to vote "yes" to the constitution was trapped inside his mosque by angry opposition supporters.

In the capital, Cairo, both sides made low-key final efforts to rally supporters.

Flag-waving Islamists gathered peacefully at one of the main mosques, some shouting "Islam, Islam" and "We've come here to say 'yes' to the constitution".

Sweeping powers

Opposition supporters - who have been urged to vote "no" by their leaders - assembled outside the presidential palace.

The building remains ringed with police, soldiers and tanks after street clashes caused at least eight deaths earlier this month in violence prompted by Morsi's decision to grant himself sweeping powers in order to ram through the new charter.

The referendum will be held on two days - this Saturday and next - because there are not enough judges willing to monitor all polling stations after some in the judiciary said they would boycott the vote.

Egyptians are being asked to accept or reject a constitution that must be in place before a parliamentary election can be held next year - an event many hope can steer the country towards stability.

The measure is generally expected to pass, given the well-organised Muslim Brotherhood's record of winning elections since the fall of Mubarak. Many Egyptians, tired of turmoil, may simply fall in line and vote "yes".

If the constitution is voted down, a new assembly will have to be formed to draft a revised version, a process that could take up to nine months.

Official results will not be announced until after the second round, though it is likely that details will emerge after the first round that will give an idea of the overall trend.