Cairo (CNN) -- Egyptian authorities said Sunday they are preparing for a new round of negotiations with the man who has kidnapped two Americans and an Egyptian tour guide to demand his uncle's release from an Alexandria jail.
Gen. Ahmed Bakr, the head of security in Egypt's northern Sinai Peninsula, says Bedouin sheikhs who are acting as mediators have confirmed the hostages "are unharmed and well fed." They include Michel Louis, the pastor of a Pentecostal church in Boston; Lisa Alphonse, a parishoner at another American church; and an Egyptian tour guide.
Authorities have identified the hostage-taker as Germy Abu Masouh, a member of a prominent Bedouin tribe in the Sinai. He wants Egyptian police to free his uncle, whom Bakr said had been caught in Alexandria with a half-ton of drugs.
Bakr said negotiators include top intelligence and police officials.
"We hope to reach a resolution soon," he said. "Germy has threatened to kidnap more tourists if his demands are not met."
Abu Masouh told Egyptian news outlets that Louis, the pastor of Boston's Free Pentecostal Church of God, had been allowed to call his wife, who had been on the same bus. However, the minister's son, Daniel Louis, cast doubt on that claim Sunday afternoon.
"We have spoken to my mother, and my mother has told us that she has not spoken to my father," he said.
Michel Louis suffers from diabetes, and the family doesn't know whether he has his medication, his son said.
Another son, Jean Louis, told CNN earlier Sunday that the captive Americans were part of a group that was on its way to Israel.
"As the tour bus was in an area of the Sinai peninsula of Egypt, they were stopped by a couple of cars," Jean Louis told CNN's "Early Start Weekend" show. "In the cars were some gentlemen who got onto the bus. They detained both my father .... and another woman who was part of the group on their way to Israel."
The family is praying for the safety of their father and the other kidnap victims, he said.
"We are concerned, but we're Christians. We believe in God. We're resolved in our faith, we know that God is going to see him out of the situation," he said.
Jean Louis said the family was not aware of security concerns about travel across the Sinai, where Americans had been kidnapped and swiftly released in two separate incidents since February.
"If we were aware, I would believe we would use correct judgment not to enter that area," Jean Louis said.
Bakr said the situation "is partially the fault of the travel agency," which he said had not informed police of their route. If it had, "we would have sent a police escort," he said.
Authorities say the captives are still in the area where they were abducted.
Kidnappings and armed robberies have increased since a popular uprising ousted Egypt's long-ruling dictator, Hosni Mubarak, last year.
In a message posted on Twitter on Friday, the U.S. Embassy in Cairo said it was "in close touch with Egyptian authorities, who are doing everything they can to bring about safe release of the American tourists."
CNN's Mohamed Fadel Fahmy reported from Cairo and Saad Abedine, from Atlanta. Richard Allen Greene and Randi Kaye contributed to this story.