Egypt is due to announce the official results of a referendum on a controversial draft constitution, BBC News reports.

Early unofficial results suggested more than 60% of voters said "yes" to the document, which is endorsed by Islamist President Mohammed Morsi.

But the opposition, which says the draft favors Islamists, is demanding an inquiry into alleged voting fraud.

Egypt has seen large and occasionally violent demonstrations by the opposing sides in the past few weeks. If the constitution passes, elections must take place within three months and the deep polarization in the country is likely to continue.

In the meantime, legislative powers would remain with President Morsi.

State media reports of the results following the second and final round of the referendum suggest that some 63% of voters had backed the charter. Turnout was low, estimated at 30%.

But the opposition movement the National Salvation Front said the vote had been marred by "fraud and violations".