Istanbul: Suspicious envelopes containing a yellow powder were sent on Friday to the Belgian, Canadian and German consulates in Istanbul, prompting a security alert, officials said.

One person who opened the envelope at the Canadian mission was directly exposed to the substance, which was now being analysed by experts, Turkey’s disaster management agency AFAD said.

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

Canada has been hit by two deadly attacks this week — a hit-and-run assault and a shooting at Canada’s war memorial and parliament building.