Launched two years ago, the tool has already drawn numerous complaints from rivals alleging anti-competitive behavior.

Earlier this month, 23 job search websites in Europe urged the European Commission to temporarily order Google to stop such practices while it investigates the issue.

European Competition Commissioner Margrethe Vestager, who has handed out 8.25 billion euros ($9.2 billion) in fines to the tech giant in recent years in three separate cases, voiced concerns about the possibility of similar anti-competitive practices by Alphabet unit Google in other areas.

“We’re looking right now at whether the same thing may have happened with other parts of Google’s business – like the job search business known as Google for Jobs,” Vestager told a conference in Berlin.

Google said it had made changes to the tool following feedback in Europe, including offering direct links to a choice of job sites and linking directly to job offers available only on a single site.

Vestager said the European Commission may adopt rules to rein in tech giants if they do not play fair.

“There’s also a broader issue for our societies, of whether we think it’s right for companies like Google and others to have such control over the success or failure of other companies, and be free to use that power in any way they like,” she said.

“If we don’t, then we may find that we need regulation, to make sure that these platforms use their power in a way that’s fair and doesn’t discriminate,” Vestager said.