Samalut, Egypt (CNN) -- A policeman fatally shot a Christian man and wounded five other Christians Tuesday in an attack on a train in Egypt, officials said.
The incident occurred at about 5 p.m. when a man walked onto the train, which was stopped in the station at Samalut, about 200 kilometers south of Cairo, said Maryanne Nabil Thaki, 29, one of the victims.
She said she was seated with her sister, Maggie Nabil Thaki, 25, their 52-year-old mother, Sabah Sinot Suleiman, and Maggie's fiance, 26-year-old Ehab Ashraf Kamal. They were en route to Cairo to buy an engagement ring, Maggie Thaki said.
Seated near them was an older Christian couple, Maryanne Nabil Thaki said.
The gunman walked up and down the length of the train, then walked back to two groups of people who were seated near each other and were both Coptic Christians, she told a reporter at the Good Shepherd Hospital in Samalut, where she was being treated for gunshot wounds to the leg and the chest.
The man said in Arabic, "There is no God but God," and opened fire, she said.
The shooter fled the train, but was captured later, a spokesman for the Interior Ministry said. The suspect, a deputy policeman, was identified as Amer Ashoor Abdel-Zaher Hassan. He boarded the train in Asiut and was en route to Bani Mazar, Menya province, where he works.
The older man, Fathi Saeed Ebaid, 71, of Cairo, was killed, a local security source told the state-run Egyptian news agency MENA. His wife, Emily Hannah Tedly, 61, was in critical condition, as was the mother of the two younger women, said Dr. Petra Kamal.
All five were to be flown to Cairo for further treatment, a hospital employee said.
In front of the hospital, about a dozen Copts demonstrated in support of the victims but were dispersed by police who fired a tear gas canister that broke through a fifth-floor hospital window, said hospital employee Mina Farouk.
The attack comes 10 days after a bombing killed 23 Coptic Christians outside the Church of the Two Saints in Alexandria, Egypt, an attack that unnerved Christians and led to increased security.
Relations between the Christian minority and Muslim majority within Egypt have been tense since that New Year's Day bombing.
Those troubles were evident last Friday -- the day Coptic Christians, who follow the Julian calendar, celebrate Christmas -- when police staged a large-scale security operation outside the same church.
In a show of solidarity, some Egyptian Muslims attended the Christmas services.
Still, protests have erupted almost nightly in many Christian areas of Egypt since the bombing.
Egyptian authorities have released a sketch of a man they think was the suicide bomber in the church attack. The Interior Ministry used forensic technology to re-create the face.
About 9 percent of Egypt's 80 million residents are Coptic Christians. They base their theology on the teachings of the Apostle Mark, who introduced Christianity to Egypt, according to St. Takla Church in Alexandria, the capital of Coptic Christianity.
The religion is known for its rift with other Christians in the fifth century over the definition of the divinity of Jesus Christ.
CNN's Ben Wedeman, Housam Ahmed and Amir Ahmed and Journalist Ian Lee contributed to this report.