Two American women tourists have been kidnapped by gunmen in Egypt’s Sinai peninsula, according to security sources.

The American tourists were travelling in a small bus with three other tourists from St. Catherine’s monastery on Mount Sinai to the Red Sea resort of Sharm el-Sheikh when it was stopped by the gunmen.

One official told the Reuters news agency that the men wanted a ransom.

Bedouins kidnapped 25 Chinese workers in northern Sinai earlier this week, but released them unharmed after a day.

They were demanding the release of fellow tribesman who was jailed after the 2004 bomb attack at the resort of Taba that killed 31 people.

The Americans were reportedly travelling through the Wadi al-Sual area of Sinai, about 40 km (25 miles) from St. Catherine’s, when a vehicle carrying masked men armed with machine-guns forced the bus to stop.

The gunmen took the tourists’ money and valuables before grabbing the two women, forcing them into a vehicle and fleeing into the mountains.

Their Egyptian tour guide was also kidnapped, AFP news agency said.

The three other tourists who had been in the bus were left behind.

Police teams assisted by a military plane are searching for the Americans, state television reported.

One officer believed the kidnappings were meant to pressure the authorities to release Bedouins detained for their role in kidnapping the Chinese workers; others said the motive was financial.

Tribesmen in Sinai have been involved in a series of confrontations with security forces in recent months.

A gas pipeline from Egypt to Israel has also repeatedly been sabotaged, though Sinai’s tourist resorts have remained largely secure.