UN Secretary General Ban Ki-moon condemned excessive use of force against protestors in Egypt, the UN News Centre said on Monday.
The UN chief said in a statement he was "highly alarmed by the excessive use of force employed by the security forces against protesters."
He also called on the transitional authorities "to act with restraint and uphold human rights, including the right to peaceful protest."
Clashes between protestors and police continued on Sunday in downtown Cairo, close to governmental buildings and the parliament. The country's health ministry said ten people were killed and over 450 injured since Friday. At least 164 were detained.
The secretary general's statement comes shortly after it was announced that one of the detainees died during interrogation early on Monday.
Egyptian media quoted the victim's lawyer and other detainees as saying that the man had signs of torture on his body. A forensic examination was ordered.
Protests, demonstrations and sit-ins continued in Egypt since November 25, amid a multi-step process of parliamentary elections, the first since the overthrow of Hosni Mubarak's government. Violent clashes erupted three days ago.