Tens of thousands of Israelis have ignored the National Security Council's (NSC) warnings and are currently vacationing in Egypt's Sinai Peninsula.

Between 23,000 and 40,000 Israelis are currently vacationing in Sinai, up 20% from Pesach (Passover) last year.

Following Sunday's suicide attacks in Sri Lanka, Israel's security organizations warned that ISIS is still active, especially in southern Asia, Africa, and the Sinai Peninsula. The sources also warned that the Sinai hosts one of ISIS' most effective branches.

In a warning published last week, NSC's Counterterrorism Bureau wrote: "In addition to ISIS' activities, Al-Qaeda members in the area are encouraging attacks on Israeli targets. The serious travel warning (Level 1) issued for Sinai is still in effect."

The Bureau also called on all Israelis currently in the Sinai Peninsula to leave "immediately" and return to Israel. Families of Israelis currently vacationing in the area are asked to contact them and inform them of the travel warning.

"Anyone wishing to visit the Sinai is asked to refrain from doing so," the Bureau emphasized.