Sudan said Tuesday it has determined the whereabouts of 11 European tourists and eight Egyptians kidnapped while on a Sahara desert safari in a remote corner of Egypt, but negotiations were continuing to try to win their release.

Sudanese officials determined that the kidnappers and their captives are at a location in the deserts of northwest Sudan about 15 miles (25 kilometers) from the Egyptian border, Sudanese Foreign Ministry spokesman Ali Youssef said in Khartoum. He said an Egyptian intelligence team had arrived in Sudan in connection with the abduction.

"The two governments of Sudan and Egypt agree that the top priority is the safety of the hostages," Youssef said. Negotiations are ongoing, he said, adding that the identity of the kidnappers was not known. Germany is conducting the negotiations, according to Egyptian officials.

The kidnappers are demanding up a ransom of up to $15 million dollars, the Egyptian state news agency MENA reported.

Tourism Minister Zoheir Garana said Egyptian and Sudanese security forces are "sweeping the area" searching for the tourists, but did not raise the possibility of a rescue operation.

One senior Egyptian security official said members of tribes in the Egypt's Western Desert and near the border were being question to try find clues on the kidnappers. Another official said authorities were also trying to determine what sort of weaponry the kidnappers have. The officials spoke on condition of anonymity because they were not authorized to talk to the press.

It was the first such abduction of tourists in Egypt, a country that was plagued in the 1990s by Islamic militant bombings and shooting against tourists. The militant violence was largely suppressed a decade ago, and Egyptian officials underlined that the kidnapping was not connected to terrorism, but was by "criminals" seeking ransom.

It was more unusual because it took place not in the well-traveled pharaonic sites along the Nile River, but at one of Egypt's most remote and little-visited natural attractions in the remote southwest corner of Egypt, near the Libyan and Sudanese borders.

The tourists were visiting Gilf al-Kebir, an isolated plateau in the Sahara desert famed for its prehistoric cave paintings. Best known is the "Cave of the Swimmers," immortalized in the 1996 movie "The English Patient," featuring 10,000-year-old paintings of people swimming, a hallmark of an ancient time when scientists think parts of the Sahara were covered by lakes and rivers.

Armed men in SUVs snatched the tour group on Friday while they were camping near the Sudanese border, Egyptian officials said.

The five Italians, five Germans and one Romanian included at least two Italians in their 70s, as well as one 68-year-old, Italian media said. The eight Egyptians seized with them were guides, drivers and at least one security guard — whose presence is required in trips to the Gilf, located about 550 miles southwest of Cairo.

The uninhabited region is a crossroads for ethnic African tribesmen — including drug smugglers — from Libya, Sudan and even Chad. About 100 miles (160 kilometers) further south lies Sudan's Darfur region, where near constant conflicts have given rise to armed bandits notorious for robberies and hijackings.

Garana said the German government was conducting negotiations. Germany has said only that it has formed a "crisis team" on the situation.

The kidnapping was only discovered because the Egyptian owner of the tour company, who was on the trip, was able to call his German wife by mobile phone, Garana said.

He told his wife that a group of armed men, who appeared "African," drove up to the group while they were setting up their tents, an Egyptian security official said, speaking on condition of anonymity because he is not authorized to talk to the media. The owner and his wife have spoken several times since, and it was believed that negotiations with the kidnappers were being conducted through these calls.

Tourism is Egypt's biggest foreign currency earner. The industry was devastated by the 1990s' militant violence but has bounced back since. There have been no major attacks in the capital, Cairo — home of the Pyramids — or the main antiquities sites in the south in more than a decade.

But militant groups have struck since in Egypt's Sinai Peninsula, with a series of bombings of beach resorts between 2004-2006 that killed 121 people, including tourists.