The Turkish Ministry of Foreign Affairs said Monday it "learned with deep sorrow" of the death of more than 50 people during attacks in front of the Cairo headquarters of the Republican Guards, a military unit tasked with defending government institutions.
Egyptian violence escalated since last week's ouster of President Mohamed Morsi. Egyptian newspaper al-Ahram reports fighting broke out between pro- and anti-Morsi crowds protesting in front of the military headquarters.
The Turkish government said the attack could lead to "extremely serious repercussions" in the country.
"This attack, which violates basic universal values such as the freedom of expression and the freedom of peaceful assembly, is also by nature a provocation which will stoke violence," the government said.
The U.S. Embassy in Cairo said its offices were closed to the public Monday and regular consular services were suspended for the day. It said the number of protesters occupying Cairo's central Tahrir Square continued to swell.
The U.S. State Department last week said it was not taking sides in the wake of Morsi's ouster.
Ankara said it was calling on members of the international community to stand by the Egyptian struggle for democracy.
"Turkey will continue to stand in solidarity with the friendly and brotherly people of Egypt," it said.
Morsi served 13 months as the first Egyptian president elected by a democratic vote.