The European Union (EU) threatened to crack down on an agreement between Google and Facebook parent Meta for online display advertising services, saying Friday that the deal may breach the bloc’s rules on fair competition.

The EU’s competition watchdog opened a probe into a 2018 pact involving the participation of Meta’s “Audience Network” in Google’s “Open Bidding” program. The European Commission, the EU's executive arm, said the deal may be part of an effort to exclude ad tech services that compete with Google’s Open Bidding program — which would harm publishers and consumers.

“If confirmed by our investigation, this would restrict and distort competition in the already concentrated ad tech market, to the detriment of rival ad serving technologies, publishers and ultimately consumers,” European Competition Commissioner Margrethe Vestager said in a statement Friday.

The United Kingdom has launched its own inquiry into the agreement between Google and Meta. The European Commission said it has been in contact with the UK competition authority and “intends to closely cooperate on this investigation following the applicable rules and procedures."