Clashes erupted in Cairo a day after Egypt’s security forces backed away from a plan to disperse protest camps, as residents pelted Morsi supporters with rocks and bottles as they marched toward a government building.
Police also fired tear gas at the thousands of people who participated in the march; the protesters are demanding reinstatement of former Egyptian President Mohammed Morsi following his July 3 ouster.
The protesters responded by throwing rocks at police, Reuters reports. Two men wielding machetes were also seen chasing pro-Morsi crowds who were heading to the Interior Ministry building.
Fighting broke out when Brotherhood supporters tried to break into the Religious Endowments Ministry where they allege some of their members are being held, security officials and witnesses said.
Police officials say 12 Brotherhood members were arrested in the skirmish. The Muslim Brotherhood said police opened fire with live rounds, wounding five people, Reuters reports.
Egypt's interim president also swore in 20 new provincial governors on Tuesday, a move that reinforces the new leadership's authority and removes all Muslim Brotherhood members previously installed in the posts by Morsi.
Seven of the new governors appointed by interim President Adly Mansour hail from the military. In line with tradition, most of them took up posts in border governorates. But three of them were sent to other key governorates. Two took up posts in the Mediterranean cities of Port Said and Alexandria, where clashes between pro and anti-Morsi protesters have turned violent. A third was given the ancient city of Luxor, a prized tourist destination.
On Monday, Morsi supporters flooded two camps in Cairo that have been the flashpoint of unrest. Fearing a “massacre,” Egyptian police postponed a plan to break up the camps.
"We were stunned by the masses" who came to the camps, one military official told the Associated Press, speaking on condition of anonymity because he was not authorized to talk to the media.
For weeks, the government has been warning protesters to disperse, describing the sit-ins as a security threat.
The Interior Ministry has depicted the encampments as a public danger, saying 11 bodies bearing signs of torture were found near both sites. Amnesty International also has reported that anti-Morsi protesters have been captured, beaten, subjected to electric shocks or stabbed. At least eight bodies have arrived at a morgue in Cairo bearing signs of torture, the human rights group said.
Both the protesters and the security forces blame each other for using live ammunition in two major clashes near the Rabaah encampment that have killed at least 130 Morsi supporters.
Further violence threatens not only to delay the transition to a democratically-elected leadership, but could further weaken the economy after more than two years of political instability.
Morsi's Islamist backers have rejected negotiations with the military-backed government, leaving the most populous Arab nation in an uneasy limbo.
Authorities also have showed no signs of meeting key demands by Morsi's Muslim Brotherhood to release top Islamists who have been detained and face criminal investigations.
A judge on Monday ordered Morsi, who has been detained at an undisclosed location since he was overthrown, to be held for 15 more days pending investigations of charges he conspired in 2011 with Palestinian militants, a judicial official said.
Sectarian violence, meanwhile, has flared in southern Egypt, and insurgents have battled the military in the Sinai, with Morsi's removal appearing to have lifted the lid on Islamic militancy in various parts of the country.
"The country is at a standstill," said Abdel-Rahman al-Bagi, part of a group of anti-Morsi demonstrators camped in Cairo's Tahrir Square since his overthrow. "Nothing is functioning because of the Muslim Brotherhood."
The Brotherhood sought to use the momentum of support from those who joined the two pro-Morsi sit-ins Monday to organize more marches.
One protest disrupted traffic across a major bridge in Cairo. Another saw about 100 marchers in a metro station holding pictures of Morsi and demanding he be reinstated.
Protesters have been fortifying the sit-ins camps. In Rabaah, men with helmets, sticks and what appeared to be protective sports equipment guarded barricades made of sandbags, truck tires and bricks. They have also built three concrete waist-high barriers against armored vehicles.
Brotherhood spokesman Gehad el-Haddad says they have no plans to back down.
"If they disperse one, we create two," he said.
The Associated Press contributed to this report