A Canadian union that successfully unionized one warehouse accused the company of closing its sites to fend off organizing efforts in the region.

Canada has warned Amazon.com that it is reviewing business ties with the company’s cloud-computing unit following Amazon’s decision to shut down its warehouses in Quebec, leading to the layoff of 1,700 workers.

A company spokesperson said Amazon will outsource deliveries to smaller contractors. The spokesperson insisted that the decision was tied to cost savings — not the recent unionization of about 300 employees at the Laval,