Israel's anti-terrorism unit on Saturday urged the Jewish state's tourists holidaying in Egypt's Sinai Peninsula to leave immediately, citing fears of kidnap attempts.
"Terrorist elements are currently in the Sinai and preparing to abduct Israelis with the aid of people in local Bedouin tribes," said a statement from the unit, which reports to the prime minister's office, cited by media.
It said the groups planned to kidnap Israelis with the aim of exchanging them for prisoners held in Israeli jails.
The move came after an Israeli warplane launched a missile in the early hours of Saturday at a car travelling in the southern Gaza Strip, killing three members of the Hamas armed wing.
An Israeli military spokesman said the raid, planned jointly with the Shin Bet domestic security agency, was a pre-emptive strike against militants planning to kidnap Israelis during the coming Jewish festival of Passover.
"An Israel air force aircraft hit a Hamas terror cell... planning to carry out kidnapping attacks in the Sinai Peninsula and in Israel during the Passover holiday," he told AFP.
The Sinai coast of neighbouring Egypt is a popular destination for Israelis during the week-long holiday, which begins on 18 April.
The Sinai has been the scene of three major bombing attacks targeting Israeli or Western tourists.
In April 2006, 20 people were killed in the resort of Dahab; in July 2005, 70 people were killed in the resort of Sharm el-Sheikh; and in October 2004, 34 people were killed in Taba, hard by the Israeli border.