The website of the largest telecoms provider in Indonesia has been defaced with an offensive post.
Visitors to Telkomsel's site on Friday morning were greeted by a profanity-laden message criticising the company.
The perpetrator also replaced the text that shows under Telkomsel's name and description in search engines, with an explicit message.
Telkomsel said it was repairing the site and investigating the incident.
BBC Indonesia reported that by 08:35 local time (02:35 GMT) the message had been replaced by a notice from Telkomsel explaining that the site was "under maintenance".
The post criticised the state-owned company for its high prices and complicated mobile plans, including its video and music streaming bundles.
The message was repeated in the company's meta description, the text that appears beneath a site's name and web address in search engines.
The name displayed in search results was also changed, with the company's name replaced by an offensive phrase.
Telkomsel posted an apology on its other websites "for the inconvenience of not being able to access [the] official website" during the incident and the ensuing repairs.
"We are currently performing the necessary tracking and improvements," Telkomsel Corporate Communication vice-president Adita Irawati said in a statement.
The company's mobile network was not affected.