European Union antitrust regulators approved on Friday a $19 billion offer by Facebook, the world's most popular social network, for mobile messaging startup WhatsApp.

The landmark deal is the largest in Facebook's 10-year history and will give it a strong foothold in the fast-growing mobile messaging market, pitting it against telecoms companies.

"We have carefully reviewed this proposed acquisition and come to the conclusion that it would not hamper competition in this dynamic and growing market. Consumers will continue to have a wide choice of consumer communications apps," European Competition Commissioner Joaquin Almunia said.

Reuters was the first to report on Sept. 25 that the deal would be cleared unconditionally.