A US consulate in China was forced to suspend some operations after a suspicious envelope was found containing an “unidentified substance”.

Operations in the southern city of Guangzhou were temporarily suspended after a staffer found an envelope at a section of the consulate not open to the public , deputy US embassy spokesman Justin Higgins told AFP.

The package was opened and a substance, reportedly “white powder”, spilled onto the clothing of the staff member. The office was immediately evacuated. “We have not yet identified the substance,” Higgins said.

The consulate issued a notice saying that the office would be closed until an investigation could be completed. No one was reported hurt but the consulate said they would take “all precautionary measures” to handle such situation.

The Guangzhou consulate is one of the busiest in the consular service, handling millions of immigrant visas and documents relating to adoptions from China.