The US consulate in Istanbul also received an envelope of suspicious yellow powder, but the building was not evacuated, a US State Department spokeswoman confirmed in Washington, DC.

Seven people from the Canadian consulate had been taken to hospital as a precaution after one of them opened a package and was exposed to a yellow powder, according to Dogan Eskinat, a spokesman for AFAD, Turkey's emergence management agency.

But the Health Ministry said 10 people from the Canada Consulate had been taken to hospital.Dogan said that as part of standard procedures, Turkish authorities had sent samples for testing.

Claude Rochon, spokeswoman at Canada's Department of Foreign Affairs, Trade and Development, said that the entire Canadian consulate team was safe.

The German Foreign Ministry said that the German consulate in Istanbul received a "suspicious object," but staff members are safe.

The Governorate of Istanbul said 14 consulate officials in total had been taken to hospital as a precaution for observation.The Health Ministry statement said that those taken to hospital are in good condition, but they will be kept under observation until the content of the powder is determined.

The powder was sent to Ankara for investigation and results are expected to be announced on Monday.

There was no immediate claim of responsibility but the incident came amid mounting concerns about the growing national security threat posed by terrorists returning from war-ravaged Syria and Iraq.