Israel has urged its citizens in Turkey to leave as soon as they can.

The Israeli Counter-Terrorism Bureau advised visitors to Turkey to “avoid crowded tourist areas, follow instructions of local authorities and get out as soon as possible”.

According to Israeli media, the warning followed a “sharpening of the high level of threat in Turkey”.

The risk of a terrorist attack targeting Israeli has been raised to level one, the highest category.

“Real and immediate terror threats remain throughout the country,” the bureau said in a statement.”

It stressed that the danger applied not just to Istanbul, but to “all tourism sites in Turkey”.

The warning comes after last month’s terrorist bombing in central Istanbul in which three Israeli tourists were killed and several others wounded.

The were reports that Islamic State was planning a attack on an Istanbul synagogue and Jewish school.

Turkey is a popular holiday destination for Israelis, with tens of thousands of Israelis visiting every year. A surge in tourists from Israel is expected over the Passover period.