Israel has warned its citizens to immediately leave Sharm el-Sheikh and Egypt's other Red Sea resorts, saying there is an imminent threat of an Isil attack against tourists.
Several hundred Israelis are currently in the region but thousands more are expected to head to Egypt's beaches during next month's Passover holiday, the Israeli government said.
The country's counter-terrorism bureau said: "There is a serious and current threat of terror attacks being carried out against tourists, notably Israelis, in the immediate future."
It urged its citizens who were in the Sinai to immediately return home and warned anyone with plans to travel to the area to cancel them. "We don't want to cry wolf, we really believe that the threat is serious," said Eitan Ben-David, the head of the counter-terror bureau.
Israel's government said it did not have "specific warnings" of a particular plot but judged that the overall danger of an attack was high.
Isil's Egyptian affiliate, known as Sinai Province, has grown increasingly brazen in recent months. Its members are believed to be responsible for a co-ordinated killing campaign against Coptic Christians in the Sinai, where Islamist gunmen have worked their way through a list of Christian targets.
This month it briefly set up a checkpoint in the city of Arish in a display of force designed to show its ability to defy Egypt's security forces. Ten Egyptian soldiers were killed last week by a pair of roadside bombs in Sinai.
While Israeli tourists are always a prime target for jihadist attacks, the Israeli government believes they may be especially in the cross hairs because of reports that Israel has carried out drone strikes against Isil in the Sinai. Israel also warned against travel to Turkey. "As long as [Isil] is in distress, it will try to carry out attacks around the world - against the Christians, the Crusaders and maybe the Jews," Mr Ben-David said.
Meanwhile, Hamas has launched a manhunt in the Gaza Strip following the killing of one of its military commanders, which the group says was carried out by Israeli assassins.
The lslamist militant organisation has placed Gaza on lockdown as it hunts for the killer of Mazen Faqha (38), who was shot dead on Friday.
While it searches for the alleged Israeli hit squad - and any Palestinian collaborators - Hamas is preventing men younger than 45 from leaving Gaza and imposed a media blackout on details of its investigation.
Israel has neither confirmed nor denied any role in the killing but Faqha's death has raised tensions in Gaza and the Israeli military is bracing for potential retaliation. "Israel decided to change the rules of the game, and we accept the challenge," said Khaled Meshal, the head of Hamas's political wing. (© Daily Telegraph London)