Israel’s Anti-Terrorism Bureau warned all Israeli tourists to leave Sinai in Egypt as soon as possible on Tuesday, due to a serious terror threat.

Defence officials said that the Egyptian security forces were making a “serious attempt” to clamp down on the terror cells in Sinai but that a number of terror groups were operating in the peninsular almost at will.

Last May, the Egyptians tracked down a large Hizbollah cell planning attacks on Israeli tourists. Cells affiliated with al Qaida are also believed to be trying to kidnap Israelis with the aim of smuggling them through the tunnels under Rafah into the Gaza Strip.

The cells in Sinai are co-operating with local Bedouin smuggling rings and the Palestinian organisations in Gaza, as well as smaller local groups that hope to bolster their image by holding an Israeli prisoner.

Egypt has been building a steel barrier beneath the Rafah border to block the tunnels but its security forces are reluctant to take on the Bedouin gangs since they have, in the past, carried out attacks on tourist resorts in revenge.

Hamas, worried by the possibility of renewed Israeli attacks, ordered the tunnel operators to close them down on Wednesday.