Top U.S. and U.N officials on Sunday expressed alarm at reports of deadly clashes between security forces in Cairo, Egypt and protesters as the country moves from military to civilian rule.

The clashes have been taking place for three days.

Secretary of State Hillary Clinton said she was deeply concerned and called on security forces to respect peaceable expression and assembly.

“We call upon the Egyptian authorities to hold accountable those, including security forces, who violate these standards,” she said.

She also called on protesters to make their concerns known peacefully and refrain from violence.

“Out thoughts are with the families of those who have been killed or injured,” she said.

A spokesman for U.N. Secretary General Ban Ki Moon said Ban was “highly alarmed by the excessive use of force employed by the security forces against protesters and calls for the transitional authorities to act with restraint and uphold human rights, including the right to peaceful protest.”

Egypt is in the midst of holding parliamentary elections ahead of a 2012 presidential election. Some protesters have been calling for an immediate transition to civilian rule.