BRUSSELS (Reuters) -EU antitrust regulators have delayed fining Alphabet's Google over its adtech business, while waiting for the United States to cut tariffs on European cars as part of a trade deal, three people with knowledge of the matter said on Tuesday.

Tariffs on cars were a big part of the negotiations that led to a trade deal between the United States and the European Union. 

The executive European Commission last week proposed to scrap tariffs on imported U.S. industrial goods and it expects an announcement soon from the United States on its promised cut in U.S. tariffs on European cars to 15% from 27.5%.

At the same time, U.S. President Donald Trump has threatened to retaliate against the EU for any push against Big Tech.

Google was told on Friday that EU antitrust chief Teresa Ribera would announce the fine on Monday but the announcement was not made and no explanation was given to the company, another source said.

One of the sources said the delay was not expected to last more than a month and three said it was caused by EU trade commissioner Maros Sefcovic asking questions about Ribera's decision without commenting on the delay's length. 

They asked not to be named because they were not authorised to speak publicly on the issue.

Germany's Monopolies Commission called the delay to the announcement an alarming precedent for the independence of European antitrust enforcement.

"The protection of competition must not become a pawn of the Trump administration," its chairman Tomaso Duso said in a statement.

European Commission spokesperson Arianna Podesta told a daily news conference the Google investigation is ongoing and declined to comment further.

Google also declined to comment.  

Google faces a modest fine for allegedly favouring its own advertising services over rivals following a four-year long investigation prompted by a European Publishers Council's complaint, other people had told Reuters last week.

MLex was the first to report about the delay in the EU decision.