RCMP officers in Quebec are carrying out a raid in Saint-Hubert, on Montreal’s South Shore, in connection with a letter that was contaminated with the poison ricin and sent to the White House.

Law enforcement cordoned off a lengthy stretch of a street lined by condo buildings in the suburban municipality. Local police and ambulance services were also at the scene.

The RCMP said a team with expertise in handling chemicals and explosives is leading the investigation to ensure the safety of the public.

Longueuil police, a local police force assisting with the operation, said on Twitter they were helping to carry out the search on Vauquelin Street and that residents in condominiums had been evacuated. 

A woman suspected of sending an envelope containing the poison ricin, which was addressed to the White House and U.S. President Donald Trump, was arrested over the weekend at the Peace Bridge border crossing between Fort Erie, Ont., and Buffalo, N.Y.

The letter was intercepted before it reached the White House.

Authorities say the letter containing ricin was intercepted before it reached the White House. (Patrick Semansky/The Associated Press)

The woman was taken into custody by U.S. Customs and Border Protection officers at the Peace Bridge border crossing near Buffalo, and is expected to face federal charges, law enforcement officials told The Associated Press.

Her name was not immediately released.

An RCMP spokesperson told CBC News on Saturday that it was assisting the FBI in the investigation and that “initial information from the investigation suggests that the letter originated in Canada.”