BRUSSELS (Reuters) - Alphabet unit Google was hit with two charges of breaching landmark EU rules on Wednesday, as antitrust regulators continued their crackdown against Big Tech.

The move by the European Commission came amid tensions with U.S. President Donald Trump who has threatened to levy tariffs against countries which impose fines on U.S. companies.

Google has been in the European Commission's crosshairs since March last year over whether it restricts app developers from informing users about offers outside its app store Google Play and whether it favours its vertical search services such as Google Flights.

The EU competition watchdog on Wednesday issued preliminary findings charging Google of allegedly breaching the Digital Markets Act which aim to rein in the power of Big Tech, confirming a Reuters story on Feb. 21.

The first charge concerned Google's practices on its app store Google Play. Regulators said Alphabet technically prevents app developers from freely steering consumers to other channels for better offers.

They said a service fee charged by the company for facilitating the initial acquisition of a new customer by an app developer via Google Play go beyond what is justified.

In the second charge, regulators said Google favoured its own services such as Google Shopping, Google Hotels and Google Flights over rivals.

"The two preliminary findings we adopt today aim to ensure that Alphabet abides by EU rules when it comes to two services widely used by businesses and consumers across the EU, Google Search and Android phones," EU antitrust chief Teresa Ribera said in a statement.

Google has previously said some airlines, hotels and retailers have voiced concerns about the impact of the DMA.

The company, which has been fined more than 8 billion euros ($8.7 billion) by the EU in the last decades for various antitrust violations, risks fines of up to 10% of its global annual sales if found guilty of breaching the DMA.

($1 = 0.9163 euros)