Credit: Getty Images

A Bedouin tribesman says he kidnapped two Americans tourists from Boston on Egypt's Sinai Peninsula in an attempt to get his uncle freed from prison, and says he will kidnap more people if his demand is not met.

The two Americans who were kidnapped at gunpoint Friday are 61-year-old Michel Louis, the pastor of the Free Pentecostal Church of God in Dorchester, Mass., and 39-year-old Lisa Alphonse. Louis' son said his father has diabetes and may require medical attention soon.

According to his son, Michel was on a missionary trip to Israel, which he does every year, and happened to venture into Egypt this time. His wife accompanied him on the trip, and is still in Egypt.

"We're in good spirits because we know the God that we serve is in control of the matter," Jean Louis, Michel Louis' son said in a press conference.

Jirmy Abu-Masuh, 32, of the Tarbeen tribe, said in an interview that he stopped their tour bus and also kidnapped their 28-year-old tour guide Haytham Ragab as well so he could translate.

Abu-Masuh told The Associated Press that the Americans are being treated well - they've been given tea and a traditional Bedouin meal of lamb - but they won't be released until his uncle, who is in an Egyptian prison, is released as well. He also said that if his uncle is not released, he will abduct more people.

"If my uncle gets 50 years (in prison), they will stay with me for 50 years. If they release him, I will release them," he told the AP. "Tomorrow I will kidnap other nationalities and their embassies will be notified for the whole world to know."

Officials at the American embassy in Cairo says they're working closely with the Egyptian authorities to free the two Americans.

Lawlessness has risen dramatically in the Sinai Peninsula, particularly since the fall of President Hosni Mubarak. Kidnappings by Bedouins have become more frequent - they also traffic in guns and drugs. Al Qaeda is known to operate in the region, though they are not believed to have been involved with this kidnapping.

This is the third time this year that American tourists have been kidnapped in the Sinai Peninsula. In early February, two American women were kidnapped and released six hours later after negotiations between Egyptian authorities and the kidnappers. In late May, two American tourists were kidnapped and released the next day.

Meanwhile, Secretary of State Hillary Rodham Clinton is in Egypt to meet with Egypt's new Islamist president, Mohammed Morsi.

ABC News' Alexander Marquardt and The Associated Press contributed to this report.