BRUSSELS?The European Union's antitrust regulator Monday said it is quizzing the U.K. government on the assurances it gave Nissan Motor Co. that convinced the Japanese car maker to keep producing cars in the U.K. after Britain leaves the bloc.

European Commission spokesman Alexander Winterstein said the antitrust regulator is "in contact" with U.K. authorities after Nissan, owner of the U.K.'s largest car factory by volume, said in late October that "support and assurances of the U.K. government" were behind the company's decision to produce two new models at its Sunderland plant.

Nissan's decision has ensured the jobs of 7,000 people and follows a meeting between Nissan's Chief Executive Carlos Ghosn and Prime Minister Theresa May in October. Nissan had threatened to move production of the Qashqai model out of the U.K. amid fears of higher taxes when the country leaves the EU.

It is still unclear what form of support the U.K. government has promised the company, but the move has raised questions whether Britain may be breaching EU state-aid rules by handing the company selective support that could give it an unfair advantage over its rivals.

"We follow events, press reports. If we see something interesting, then we ask questions," Mr. Winterstein said Monday.

The EU's state-aid rules apply to the U.K. as long as it is still a member of the bloc, and would also likely still apply if both sides agree to grant the U.K. access to the internal market after it formally leaves the bloc.

Under EU rules, member states are generally requiredto notify state-aid support to the commission before implementation.

Mr. Winterstein said the British government hadn't formally notified the commission of any state aid support in this case for the regulator's assessment.

"Therefore we haven't taken any formal view on this matter," he said.

The U.K. government said it was in regular contact with the European Commission on a range of issues. "As the European Commission themselves have said, exchanges like these are common," a spokesman for the Department of Business, Energy and Industrial Strategy said in a short statement.

Nick Winning contributed to this article.

Write to Natalia Drozdiak at natalia.drozdiak@wsj.com

(END) Dow Jones Newswires

November 07, 2016 11:45 ET (16:45 GMT)

Copyright (c) 2016 Dow Jones & Company, Inc.