Christian homes were attacked and set on fire in Egypt after rumours circulated that a Christian man had an affair with a Muslim woman, according to the Orthodox Coptic Church.

Around 300 armed people attacked seven houses owned by Christians in Al-Karm village in Minya province, south of Cairo, on May 20, the diocese of Minya and Abu Qiras said in a statement.

"The attackers also stripped an old Christian woman of her clothes in front of a huge crowd in the street," the diocese said. This woman was the mother of the man alleged to have conducted the affair. According to Daily News Egypt, she was 70 years old, and was dragged into the road and beaten.

"His parents already filed a complaint at Abu Qiras police station about receiving threats on 19 May and that they expected those threats to happen the next day," the statement continued, noting that the man had been forced to leave the village.

"We trust that such behaviour is not accepted by any respectable person; we also trust that the state apparatuses won't stand by as a spectator and thus we thank in advance the security apparatuses as we believe it will all arrest all those involved and hold them accountable."

Six people have been arrested in connection with the incident.

However, Tarek Nasser, the governor of Minya, has downplayed the events. According to AP, he denied that an elderly woman had been stripped naked.

"Some irrational youth threw flammable missiles at the houses of Christians in the village and some women ran away in their nightgowns," he said in a statement to the media.

Pope Tawadros II, Pope of the Coptic Orthodox Church of Alexandria, said on Thursday he had been assured the attackers would be brought to justice.

Christians, mostly Orthodox Copts, account for about 10 per cent of Egypt's population, which is overwhelmingly Sunni Muslim.

Sectarian violence sometimes erupts over disputes on issues related to church building, religious conversions and interfaith relationships.

The United States Commission on International Religious Freedom (USCIRF) earlier this month recommended that the US State Department add Egypt to its list of "countries of particular concern", where "particularly severe violations of religious freedom are perpetuated or tolerated".

Though the Egyptian government has taken "positive steps to address some religious freedom concerns" in the past year, there remains a "climate of impunity," the USCIRF said.