An Egyptian police officer has killed a 71-year-old Christian and wounded five other people in a shooting on a train travelling between southern Egypt and the capital Cairo, sources have said.
It was not immediately clear if Tuesday's shooting was motivated by religious issues in the Muslim majority country, where tensions between the two communities has risen after the New Year's Eve bombing of a church in the northern city of Alexandria that killed 23 people.
An interior ministry statement named the assailant as Amer Ashour Abdel-Zaher, a 23-year-old Muslim officer.
It also named the man killed and the five others wounded, saying one of those injured was the dead man's wife.
The husband and wife were from Cairo, while the others were from the central Minya province. At least two of the names suggested that they were Christians.
Suspect 'ran away'
The statement said that Abdel-Zaher, who was not wearing a uniform, was on his way to work at a town near Samalout in Minya province, when he boarded the train and "opened fire on some train passengers from his pistol and ran away".
Police arrested him at his nearby home he was being questioned, according to the ministry statement.
Soon after the attack, hundreds of angry Copts gathered outside the hospital where the wounded were being treated and pelted the police with stones.
Assiut, where the train set off from, is home to a substantial Christian community and a famous monastery.
Ayman Mohyeldin, Al Jazeera's correspondent in Cairo, said that the authorities were keen not to jump to conclusions about the motive for the attack.
"The January attack is fresh on everyone's mind. There are going to be a lot of questions whether it [Tuesday's shooting] was religiously motivated," he said.
The incident comes as Egypt faced expressions of concern from the international community over the safety of its Christian population and recalled its ambassador to the Vatican following comments by Pope Benedict XVI.
In a speech on Monday, Benedict cited recent attacks on Christians in Egypt, Iraq and Nigeria, and said governments must take effective measures to protect religious minorities.
Hossam Zaki, a spokesman for Egypt's foreign ministry, described Benedict's remarks as "unacceptable'' and accused him of interfering in the country's internal affairs.
Hosni Mubarak, Egypt's president, has repeatedly said that the government will do its utmost to protect Egypt's Christians and has accused foreign groups of being behind the New Year's Eve church bomb.
The church attack reopened long festering wounds in a Christian community that often says it feels like it members are second class citizens in their own country.
Coptic Christians demonstrated around the country, including in Assiut, in the aftermath of the bombing and called for better protection and equal rights.