Egypt extended an overnight curfew around the Defense Ministry on Sunday to deter a repeat of Friday's deadly violence, less than three weeks before a presidential vote.

A soldier died and almost 400 people were wounded in Friday's clashes, the second time in a week that protests over the army's handling of Egypt's troubled transition from army rule to civilian government have turned violent.

The military re-imposed the curfew in the Abbasseya district around the Defense Ministry for the third straight day, the state news agency quoted a military source as saying.

Running from 11 pm to 6 am, it is an hour shorter than on the previous two nights.

A presidential election, which starts on 23 May, will choose a replacement for Hosni Mubarak, who was toppled in February last year. Generals have governed since then and their rule has been punctuated by unrest, sometimes violent.

Many protesters who gathered near the ministry were ultra-orthodox Salafi Muslims furious that a sheikh they backed for president has been disqualified from the race. Liberals and others were also there, accusing the army of seeking to manipulate or delay the vote.

The military has dismissed those allegations, insisting it will stick to its timetable of handing over power to a new president by 1 July, or even earlier in the unlikely event of an outright winner in the first round of voting this month.