The landmark European Union law would force major tech firms to change their ways in a way that regulators hope will create a fairer market.

Coming into force next month, the Digital Markets Act (DMA) designates six "gatekeepers" facing the curbs: Google parent Alphabet, Amazon, Apple, Meta, Microsoft -- and ByteDance, the only non-US company.

TikTok filed a legal challenge against its designation in November.

The platform owned by China's ByteDance asked the Luxembourg-based General Court last year to suspend its obligation to comply with the DMA while its case is ongoing.

"ByteDance has failed to demonstrate the urgency required for an interim order in order to avoid serious and irreparable damage," the court said in a statement.

The company had argued that complying with the "contested decision risks causing the disclosure of highly strategic information concerning TikTok's user profiling practices, which is not otherwise in the public domain", the court added.

A TikTok spokesperson said the company was "disappointed with the decision" but added: "We look forward to having the substance of our case heard on an expedited basis."

TikTok has been preparing for compliance and will continue to do so, the spokesperson said in a statement.

The DMA also identified 22 "core" platforms provided by companies including Facebook, Instagram and several Alphabet products including YouTube.

TikTok is not the only firm that is challenging the EU in the courts over the labels.

Meta is also contesting the designation of its instant messenger service Messenger as a "core platform service", and its Facebook Marketplace.

TikTok and Meta this week also said they would take legal action against the EU over a fee that the world's biggest tech companies must pay under a content moderation law.

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