israel-turkey
People stroll at Istiklal street, a major shopping and tourist district, in central Istanbul, March 22, 2016. A Turkish flag, which is placed on the stall of a street vendor, is seen on the right. REUTERS/Osman Orsal

Israel urged its citizens in Turkey on Monday to leave "as soon as possible" in an upgraded travel advisory predicting possible follow-up attacks to the March 19 suicide bombing in Istanbul blamed on Islamic State group.

Three Israeli tourists and an Iranian were killed in the Istanbul attack, which prompted the counter-terrorism bureau in Prime Minister Benjamin Netanyahu's office to issue a generalized "level 3" warning against travel to Turkey.

A statement by the bureau raised this to "level 2" on Monday, signifying what it called a "high concrete threat" that Islamic State or similar groups would attack Turkish tourist attractions. It did not elaborate on what prompted the alert.

The statement said Israelis should avoid going to Turkey and, if already there, "depart as soon as possible."

If a "level 1" alert were by issued by Israel, that would urge citizens to leave the country "forthwith."