At least 25 people have been killed in a tourist city in southern Egypt following four days of clashes between local ethnic groups, according to government officials.

Fighting began on Friday in Aswan between Arab and Nubian families and continued over the weekend despite Egypt's prime minister and chief of police travelling to the area to co-ordinate the state's response.

Violence had subsided by Sunday evening – but not before dozens had been shot or stabbed, leaving 25 dead and 56 injured. Photographs from the city – known for its rich pharaonic history – showed homes and cars torched and looted.

An army spokesman claimed on social media that the violence was sparked by the Muslim Brotherhood – a common government claim after outbreaks of violence. But two Aswan residents said by phone that the tensions were localised, and stemmed from an argument between students from a local Arab family and one from Aswan's long-marginalised Nubian community.

Reports differed as to who struck first. But one Nubian resident claimed that members of an Arab clan – the Haleyla – had daubed anti-Nubian graffiti on a wall on Thursday, after a group of Nubian students walked through their neighbourhood to get to school.

"They wrote some provocative phrases on the walls, saying that they are the masters of the place," said tourism worker Abdallah Ghareeb Madany, who claimed members of the Haleyla later returned and started firing at local Nubians, killing at least one.

The next day, said Madany, the Nubian community retaliated – entering a Haleyla area and killing "whoever they could find". Twenty-four hours later, members of the Haleyla responded in kind in a Nubian area – with accounts suggesting that the police had done too little to quell the violence.

Nubian people lived historically in southern Egypt and northern Sudan, and have their own dialect and traditions. In Egypt, the community has long felt ostracised after being forcibly displaced from their homeland by a series of evictions throughout the 20th century – most notably by the construction of the Aswan dam in the 1960s, a move that upended their lives and culture.

Attempting to contextualise the recent Aswan violence, prominent Nubian writer Hagag Odul wrote on social media: "The four displacements shocked our existence especially the displacement of 1964 that removed us from our roots around the banks of the Nile and threw us in the desert among armed groups… We were insulted, and called black and barbaric.

"We had to be like them, to carry guns and threaten to use them in order to defend [ourselves], in order to be citizens like other citizens."

Additional reporting by Manu Abdo