Two people were killed on Sunday when tribal clashes flared for a third day in the southern city of Aswan, security sources said.
At least 25 people have now been killed in the violence between members of the city's two big tribes, the Nubian and the Arab Beni Helal clans.
The prime minister and interior minister travelled to Aswan on Saturday afternoon to try to quell the tension as residents demanded an end to the bloodshed.
The two sides fought guns and petrol bombs, and several houses and shops were burned to the ground before the police and army were able to briefly stop the fighting on Saturday morning.
Nubian clan members blocked a main street with burning car tyres on Sunday, and members of the Beni Helal tribe set ablaze carts on another main road, witnesses said.
Aswan is a tourist city 900 km (550 miles) south of Cairo on the River Nile.
"We want the government to take action, not come for a short visit and go away," said Ahmed Rafeat, a Nubian who works in the tourist industry. "We ask for security, an end to the bloodshed and a curfew to be imposed."
Seventeen of the dead were from the Beni Helal clan. The army said on Saturday there were "signs of involvement" of the Muslim Brotherhood - the Islamist movement of deposed President Mohamed Mursi - in the strife.
The Islamist group denies any links to the violence that spread to many Egyptian cities after Mursi's overthrow last July.
Authorities have cracked down on the group since then and have jailed thousands of Islamist activists and killed hundreds more, mostly during the forced dispersal of protest camps set up by Mursi supporters in Cairo last August.