Turkish emergency services were called to the Hungarian Consulate in Istanbul on Monday morning as reports emerged of a suspicious letter containing yellow powder having been opened in the building.

The city’s provincial governorate confirmed that an emergency team was sent to the consulate in the Levent district of Istanbul, a commercial center.

There are no immediate reports of any injuries.

Today’s alert brings to six the number of consulates which have received suspicious items containing an unidentified yellow substance. Toxicology test results from five other consulates Friday are expected today in Ankara.

It is thought that today’s letter had arrived on Friday -- included in the original wave of suspicious packages -- but had lain unopened until this morning.

Letters containing a yellow substance were delivered to the Canadian, German, Belgian, French and American Consulates on Friday, sparking fears of a chemical attack. 

Twenty-five staff members from the various consulates were hospitalized for observation. There have been no reports of any injuries so far.

Anadolu Agency