A woman who threw pumpkin seeds at Prime Minister Justin Trudeau in Hamilton was detained for questioning after being tackled to the ground by security.

Trudeau was leaving city hall after meeting with Mayor Fred Eisenberger, when the woman hurled the seeds at him, shouting, "Keep your promises!"

She was immediately tackled to the ground by security as Trudeau's detail whisked him to his motorcade.

Earlier, she had been holding a banner reading "No New Pipelines" with a man who identified himself as David Johnson.

He said they want to know why Trudeau has "not yet reformed the National Energy Board or shut down their proceedings."

Johnson did not know why his fellow protester was carrying pumpkin seeds.

RCMP officers took the woman into a meeting room at city hall for questioning, but it is not clear if she faced charges. The RCMP directed further inquiries to Hamilton police, who "made the arrest." Hamilton Police did not immediately respond to a request for comment.