The general-secretary of the committee overseeing Egypt's constitutional referendum on 15 December has threatened to step down if more violence erupts before or during polling.
Zaghloul El-Balshi, who was appointed by President Morsi, said he had instructed judges supervising the referendum to close polling stations and go home if violence erupts during the vote.
Egyptians should refrain from protesting and express their view on the constitution via the ballot box, he added.
Protesters have taken to the streets for the past two weeks calling for President Morsi to cancel both the referendum and the controversial decree that put his decisions beyond judicial scrutiny. There have also been mass protests in support of the president.
Despite calls by the opposition to cancel the referendum, El-Balshi said preparations were already underway. Egypt has approximately 51 million eligible voters, he added