San Francisco, Nov 10 (DPA) Google is to pay $750 million to buy AdMob, a provider of advertising on mobile phones, the internet search leader announced Monday.

The deal is the third largest ever undertaken by Google and underscores the company's strategy of extending its online advertising dominance to the mobile web, where its Android smartphone operating system is becoming increasingly popular. Google said it expected antitrust regulatory review in the US but not in Europe.

AdMob has a system that serves display ads on mobile phones and its purchase could give the still nascent market a powerful boost, analysts said.

"Google could have built this itself, but this gives them a head start," says mobile analyst Greg Sterling of Sterling Market Intelligence. "It will thrust Google into the forefront of mobile display ads."

"AdMob is a great Silicon Valley story," said Google in a blog posting to announce the deal. "We are looking forward to having them join the Google team and work with us on the future of mobile advertising."