“The US diplomatic mission in Turkey has received credible reports of potential terrorist attacks, as well as abductions of American and foreign citizens in Istanbul.
The threat is directed, among other things, against the US Consulate General, ”the statement on the US Embassy website says.
It is noted that "all visa services at the US missions in Turkey (including the embassy in Ankara, consulates in Istanbul, Adana and Izmir) will be temporarily suspended."
The embassy encourages US citizens to exercise extreme caution in areas where Americans or foreigners may congregate, including large office buildings or shopping centers.