Cairo: Egyptian authorities on Wednesday denied that a Muslim policeman, who killed a 71-year-old Christian man and injured five others aboard a train, was acting according to a religious motive.

"I do not think there is a religious motive for this man, who shot randomly at passengers of the train," the official Middle East News Agency quoted the governor of Minya in Upper Egypt, where the attack occurred on Tuesday night, as saying.

Prosecutors on Wednesday ordered that policeman Amer Ashour, who attacked the Cairo-bound train with his service weapon, be kept in custody for 15 days pending further investigations.

They said that the defendant faces charges of murder and the misuse of his service weapon.

The attack came less than two weeks after a bombing outside a church in the Egyptian coastal city of Alexandria left 23 Coptic Christians and many others injured. 

Tuesday night's attack enraged local Copts who protested outside the hospital to where the injured had been taken, according to local eyewitnesses.

The assailant told investigators that he had felt frustrated at the time of the crime because he had a financial problem, police sources said on Wednesday.

"The crime has to do with his mental state and not with the religion of the victims," said Governor Diaa Eddin.

Coptic survivors, however, said that the attacker had singled out women wearing no hijab and shot at them.

The five injured Copts were transferred to Cairo for treatment, medical sources said on Wednesday. Two of them are kept in intensive care units, they added.

Christians make up around 10 per cent of Egypt’s 80 population and their relations with the Muslim majority have recently been marred by tensions due to religious conversions and disputes over the construction of places of worship.