MONTREAL -- Quebec tax authorities have raided two Montreal offices of Uber, the company that offers rides at prices lower than typical cab fares.

About 20 investigators executed search warrants on Thursday seeking tax-related documents, said Stephane Dion, a spokesman for the province's revenue agency.

"The investigation has been going on for several months," Stephane Dion said in an interview.

"At the moment we have 20 investigators on the premises of Uber Canada Inc. The goal is to obtain as much information as possible and these documents will then be analyzed. After that, we'll be able to determine whether charges will be laid.

"Revenu Quebec is responsible for applying tax laws. We have the power to recommend that charges be laid. And they can be accompanied by fines and prison sentences of up to five years if individuals or the company are found guilty."

Dion refused to say whether any individuals were being targeted.

Asked for reaction, Uber spokeswoman Susie Heath said in an email that "we look forward to continuing to work with all stakeholders in Quebec to foster innovation, create jobs, and provide consumers with much needed affordable transit options."

The raids were conducted just more than two weeks after the City of Montreal announced it had seized 40 of the company's vehicles since the beginning of the year.

Uber's UberX service uses a smartphone app that links clients to drivers in privately owned vehicles, without a taxi licence, to provide rides that cost less than cab fares.

The city and the province consider UberX a form of illegal transport.