Singaporean traditional Chinese medicine company Eu Yan Sang had its website hacked on Thursday morning.
The message posted on its website by a hacker who went by the name "bambu", read: "Do not insult our country just because of smoke in the air in your country.
"You should not just blame Indonesia for the polluted air. Blame the wind, and who told the wind to blow to your country."
A check showed that "bambu" had also hacked into at least one other site, ineltronics.com. Both hacking instances were supported by the "Indonesia J.A.M.5 Team", according to the text on both sites.
Eu Yan Sang's website has since been restored, while ineltronics.com remains defaced.