ISTANBUL, Turkey, April 9 (UPI) -- The United States warned of "credible threats" to public areas Saturday in Istanbul, the same day a flash grenade went off near a bus station, injuring three people.
The U.S. Embassy in Turkey, in its warning announcement, said the threats are specific.
"There are credible threats to tourist areas, in particular to public squares and docks in Istanbul and Antalya. Please exercise extreme caution if you are in the vicinity of such areas," the announcement read.
Police said what they believed was a flash grenade, which generates a loud boom and burst of light, but no deadly shrapnel, was detonated after it was left under an overpass near a bus station in Istanbul. Three bystanders suffered minor injuries and were taken to area hospitals. It was not immediately clear whether the incident was intended as part of a terrorist attack or a prank. Police are investigating.
The incident prompted two nearby shopping malls to be evacuated.
The U.S. Embassy issued a general travel warning for the country just over a week ago citing increased threats from terrorist groups. The U.S. Department of State ordered a departure for the families of U.S. government personnel and limited incoming travel to "mission-critical" status.
The German government has temporarily closed its embassy, a German consulate in Istanbul and two German schools in the country over the terror threat.
In March, a suicide bomb attack killed at least four people and injured 36 more near a popular shopping district in Istanbul. It marked the fourth major blast since November and was connected with the IS, also known as ISIS, ISIL and Daesh -- according to reports.
Less than a week before the Istanbul attack, at least 37 people were killed in a suicide car bombing in the Turkish capital of Ankara. Kurdish militants claimed the attack.