Google has hailed the power of artificial intelligence and machine learning to bring greater efficiencies to job hunting. But the tools the company has created have put it in the crosshairs of rival job sites, who are accusing the search giant of antitrust abuses.

According to Reuters, a coalition of job sites has sent a letter to European regulators claiming Google’s job search system, which aggregates listings from other sites, is hurting their own traffic and business. The 23 European companies that signed the letter want EU antitrust commissioner Margrethe Vestager to issue an order halting the practices while she investigates the allegations.

The signees include U.K.-based Best Jobs Online and Germany’s Intermedia and Jobindex. The next step would be for these companies to file a formal complaint.

A more formal investigation would be the latest in a string of antitrust problems Google has faced in Europe.

Earlier this year, Google was hit with a $1.69 billion penalty for antitrust abuses related to AdSense. Last year, EU regulators fined Google $5 billion for abusing the dominant position of its Android mobile operating system to favor its own apps. And in 2017, the EU hit Google with a $2.72 billion antitrust penalty for abusing its dominance in search to boost its comparison shopping service.

Google originally announced its Cloud Jobs API in late 2016 to make it easier for companies to adopt search tools for their customers.

“In order to provide the most relevant recommendations to job seekers, Cloud Jobs API uses machine learning to understand how job titles and skills relate to one another and what job content, location, and seniority are the closest match to a jobseeker’s preferences,” Google wrote in a blog post at the time.

The following year, the company unveiled Google for Jobs.

In a blog post about Google’s advancing AI initiatives at the time, CEO Sundar Pichai wrote: “Through a new initiative, Google for Jobs, we hope to connect companies with potential employees and help job seekers find new opportunities. As part of this effort, we will be launching a new feature in Search in the coming weeks that helps people look for jobs across experience and wage levels — including jobs that have traditionally been much harder to search for and classify, like service and retail jobs.”

Google says these initiatives drive more traffic to job websites and make it easier for job seekers to find and track openings. Seekers still have to visit the sites that appear in Google for Jobs to apply.

But disgruntled sites say that if they don’t adopt Google’s tools and invest in restructuring their data to match the search engine’s requirements, they are punished with lower search rankings. And they fear Google will eventually begin running its own job ads alongside their results, further taking away business.