Two American tourists kidnapped in Egypt's Sinai Peninsula by Bedouin tribesman were released on Thursday after less than 24 hours in captivity, security and government officials told Agence France Presse.

The two men were in good health and police were escorting them to a safe place, where they were due to meet the South Sinai governor, the officials said.

Egyptian Bedouin in the Sinai kidnapped two Brazilian women tourists on Sunday in the third such abduction in the peninsula this year, security officials said.

The tourists were returning from a visit to the historic monastery of St Catherine in southern Sinai when the tribesmen seized them and an Egyptian tour guide, the officials said.

Accounts of the attacks that killed eight Israelis near the border with Egypt on Thursday paint a picture of an operation carefully planned and executed.

The triple attacks, attributed by Israel to radical Palestinian activists from the Gaza Strip, took the army and police by surprise, judging by the ensuing confusion and inaccuracy of initial reports.