Canada said it was aware hackers had breached security at a domestic manufacturer of software used by big energy companies, but declined to comment on a report that a Chinese group could be responsible.
Calgary-based Telvent, which is owned by France's Schneider Electric SA, warned customers about the attack, which hit operations in the United States, Canada and Spain, the cyber security news site KrebsOnSecurity.com reported on Wednesday.
"The Canadian Cyber Incident Response Centre is aware of this incident and is already working with stakeholders in government and the private sector," public safety ministry spokesman Jean-Paul Duval said in an e-mail late on Thursday.
KrebsOnSecurity.com cited experts who said digital fingerprints left during the attack pointed to Chinese hackers.
If a Chinese group were involved it could complicate matters for Canada's Conservative government, which is deciding whether to approve a landmark $15.1-billion bid by China's CNOOC Ltd for oil producer Nexen Inc.
Some legislators are wary of the proposed takeover, in part because of what they say are China's unfair business practices.
Mr. Duval, citing operational reasons, declined to comment when asked whether Canada thought Chinese hackers were responsible.
"We can tell you that the government of Canada is working to protect Canada's cyber networks, identify vulnerabilities and intrusions, and to defend against malicious cyber activity," he said.
An organization that regulates U.S. electric utilities is looking into the breach at Telvent, which makes software that energy companies use to manage production and distribution of electricity. Telvent acknowledged a breach had taken place but gave few details.
China is often cited as a suspect in various hacking attacks on companies in the United States and other nations. Beijing dismisses allegations it is involved.
The Canadian Cyber Incident Response Centre monitors cyber threats and coordinates the national response to cyber security incidents.