(Adds Booking response in paragraphs 3-5)

AMSTERDAM, Nov 14 (Reuters) - Hotel reservation website Booking.com must comply with strict EU obligations as of Thursday, following its designation as a "gatekeeper" under the Digital Markets Act in May, the European Commission said.

The Digital Markets Act $(DMA)$ is one of the most stringent regulations targeting tech giants' market dominance, imposing tougher obligations to moderate content, allow fair competition and make it easier for consumers to switch between services.

Booking said it was in full compliance with the new EU rules, following "intense efforts" across its business.

"We are confident that our compliance solutions satisfy the requirements of the DMA and deliver the experience that both travelers and our partners expect of us," the company said in a blog post.

"We remain committed to continuing the constructive discussions with the European Commission and interested stakeholders," it said.

The DMA designates companies with more than 45 million monthly active users and 75 billion euros ($79 billion) in market capitalisation as gatekeepers, providing a core platform service for business users.

If a gatekeeper does not comply with the DMA, the Commission can impose fines of up to 10% of the company's total worldwide turnover, which can go up to 20% in case of repeated infringements. It can also impose limits on takeover activity.

($1 = 0.9520 euros)

(Reporting by Bart Meijer Editing by Tomasz Janowski)

((Bart.Meijer@thomsonreuters.com;))