Egyptian armed forces and protesters have clashed in Cairo, with troops using water cannon and rocks to disperse demonstrators trying to reach the defence ministry.
Hundreds of troops guarding the ministry surged forward on Friday when protesters began cutting through barbed wire used to seal off the ministry building in the capital's central Abbasiya neighbourhood.
"We understand that just a few minutes ago, the protesters tried to remove the barrier with barbed wire between themselves and the defence ministry," Al Jazeera's Steve Chao reported from Cairo.
"Security forces responded with water canons. Protesters responded with rocks."
He said the military forces were describing their actions as "self-defence".
The protests come amid heightened tension after 11 people were killed in clashes that broke out on Wednesday when unidentified assailants fired at protesters staging a sit-in outside the ministry of defence in Cairo.
Protesters have plastered Cairo's Tahrir Square with banners reading, "Down with military rule".
"I’m telling the military council… enough bloodshed, enough fabricated crisis, enough unleashing of thugs on the public, enough destruction… we want them to transfer power to an independent transitional authority tomorrow,” Akrami Darwish, a protester, said on Friday.
The protests, to "protect the revolution and halt the bloodshed", are expected to draw people from all major political formations in Egypt, namely the Muslim Brotherhood, a section of the Salafist movement and the liberal activist movements.
Several pro-democracy movements, including April 6, as well as the powerful Muslim Brotherhood said they would be joining the protests in Cairo and the Mediterranean city of Alexandria.
The ultra-conservative Salafi movement, which has become increasingly popular recently, is also participating in the rallies. Its candidate, Hazem Abu Ismail, was disqualified because his mother had dual Egyptian-US nationality.
In Cairo they plan to demonstrate in Tahrir Square - the epicentre of protests that toppled president Hosni Mubarak last year - but some have said they plan to gather outside the defence ministry, prompting the army to issue a warning.
"If anyone approaches its (installations), they should hold themselves responsible," General Mokhtar al-Mulla, a member of the ruling military council, said on Thursday.
Al Jazeera’s Rawya Rageh, reporting from Cairo, said: "It has really boiled down to an issue of trust. Whatever the ruling military council promises, people simple don’t trust them, at least the protesters."
"It is definitely turning into a battle of the wills between the two sides," she said.
Handover of power
Army troops were accused of standing idly by near the clashes on Wednesday and not intervening until after the deaths of some of the protesters.
However, the army denied that it was responsible for the bloodshed.
"Our hands are clean of Egyptian blood," Major General Mohammed al-Assar, a senior official in the Supreme Council of the Armed Forces (SCAF), said on Thursday.
The ruling military council has tried to counter accusations that it might use the violence as a pretext to ignore its own deadline to relinquish control of the country.
"We say it frankly and clearly. The armed forces and their supreme council are committed to the handover of power on June 30," al-Assar said.
"We don't desire power. The Supreme Council (of the Armed Forces) is not a substitute for legitimacy in Egypt," he said.
He said the military will ensure the integrity and fairness of the presidential election.
"We are committed to fair elections [...] We don't have any [favoured] candidates. All the candidates are respectable Egyptians."
The presidential election is scheduled for May 23 and 24 and a run off for June 16 and 17 if there is no outright winner in the first round.
The military has said it would hand over power to civilian rule before the end of June, or by May if there is a clear winner in the first round of elections.
It has been accused of bungling the transition to democratic rule over the past year, with the death of more than 100 people in political violence.
The ruling SCAF cracked down on pro-democracy protests and hauled more than 10,000 civilians to trial before military tribunals.