The German consulate general in the center of the Turkish metropolis of Istanbul remained closed on Wednesday due to the increased risk of attack.
A statement from the Federal Foreign Office to German citizens in Turkey said that after incidents such as the burning of a Koran in Stockholm, the risk of terrorist attacks had increased - especially in the inner-city district of Beyoglu and around the central square of Taksim.
The Federal Foreign Office recommended being particularly vigilant and avoiding crowds and the areas mentioned.
"If you live there, limit your stay outside of the apartments to what is absolutely necessary," it said.
The Swedish Embassy in Ankara and the Consulate General in Istanbul were also closed to visitors.
The British Consulate General is also currently closed to the public.
Switzerland closed its embassy in Ankara and the consulate general in Istanbul.
There is "tangible information about an imminent terrorist attack".
Several European countries and the USA had already warned their citizens last week of an increased risk of attacks in Turkey.
The USA tightened its warning on Monday and specified Istanbul.
Turkey, in turn, had warned its citizens of attacks in Europe and the USA and tightened security precautions in its own country.
Background are several Islamophobic actions in Europe.
In Sweden, a right-wing extremist burned a copy of the Koran - the holy book of Islam - in front of the Turkish embassy in Stockholm.