Turkey's state-run news agency says an explosion near an overpass in Istanbul has slightly wounded two people.

The Anadolu Agency says Saturday the explosion occurred in Istanbul's central Mecidiyekoy district. Police cordoned off the area and the cause of the explosion was under investigation.

The explosion came hours after the United States warned its citizens about "credible threats" to tourist areas in Turkey, especially around public squares and docks in Istanbul and the Mediterranean beach resort of Antalya. The emergency message from the U.S. Consulate urged citizens to exercise "extreme caution."

Turkey has been hit by six major bombings since July that have killed more than 200 people, including a suicide bombing in Istanbul last month blamed on the Islamic State group that killed three Israeli tourists and an Iranian man.