Police are investigating a suspicious parcel sent to the office of Labour MP Mohammad Sarwar.
Mohammad Sarwar: "Upsetting incident"
The package, containing a white powder, was opened by a member of his office staff in Glasgow on Friday morning.
No-one was injured but Mr Sarwar said it was "a shocking and upsetting incident."
Police have taken the suspect package away from Mr Sarwar's office for tests.
A spokeswoman for Strathclyde Police confirmed that officers were looking into
"A suspect letter was delivered to the constituency offices of a Labour MP in
the south side of Glasgow," she said.
"The letter will be examined and police enquiries are ongoing."
The MP for Govan said he had "received hate mail in the past but that this is obviously something more serious".
Mr Sarwar is Scotland's only Muslim MP.
He was first elected in 1997.