Egypt unrest: Women protest against army violence
Thousands of Egyptian women have held rallies in Cairo against their treatment by security forces.
Demonstrators brandished photos of a woman who was beaten and dragged along the ground, exposing her underwear - an incident that has outraged Egyptians.
The rally took place in Tahrir Square, which has seen five days of deadly clashes between protesters and troops.
The ruling military council has said it deeply regrets any "transgressions" against women protesters.
On Monday, US Secretary of State Hillary Clinton accused Egypt's police and soldiers of deliberately targeting women.
Speaking in Washington, Mrs Clinton said that women were being humiliated in the same streets where they had risked their lives for the revolution.
"This systematic degradation of Egyptian women dishonours the revolution, disgraces the state and its uniform and is not worthy of a great people," she told an audience at Georgetown University.
She called the events of the past few days "shocking".
At Tuesday's rally in Cairo, some women shouted: "Our honour is a red line".
Protester Nawara Negm said the security forces were deliberately trying to humiliate women.
"They know that people who don't care about their own lives they care about their mother, wife and sister. So they wanted to humiliate the whole Egyptian people by humiliating women because they know it's very sensitive," she told the BBC.
"[The ruling generals] have to go, they are traitors."
In a statement, the Supreme Council of the Armed Forces expressed its "strong regret to the great women of Egypt over transgressions that occurred during recent incidents in the protests outside parliament and the cabinet".
Earlier, General Adil Emara, a member of the military council, said that the attack on the woman was an isolated incident and was under investigation.
"We have nothing to hide," he insisted.
The council also said it would open an investigation into accusations that soldiers carried out virginity tests on women protesters in March.
Earlier, security forces clashed with protesters who returned to protest against the military for a fifth day.
At least 13 people have been killed since the latest clashes began on Friday, just after the second round of the country's parliamentary elections.
There are reports of injuries resulting from Tuesday's clashes, but so far no deaths.
Meanwhile, a retired Egyptian army general who still acts as a military adviser, Abdul Moneim Kato, caused outrage by saying that some protesters deserve to be thrown into "Hitler's ovens".
The leading presidential hopeful, Mohamed ElBaradei, said the remarks showed a "deranged and criminal state of mind".
The military council assumed presidential powers after Hosni Mubarak was forced to step down as head of state in February.
Protesters returned to Tahrir Square in November, accusing the generals of delaying the transfer of power to a civilian government.