Singapore Telecommunications Ltd (STEL.SI), Southeast Asia's largest telecoms company, is close to acquiring a Silicon Valley-based mobile advertising startup, a person familiar with the matter said.

AdJitsu, which provides tools to make three-dimensional animated ads in mobile apps in iPhone and iPads, is in the process of being bought by SingTel's U.S.-based mobile advertising solutions subsidiary Amobee, this person said.

Amobee, also based in Silicon Valley, was bought by SingTel in March for $321 million.

AdJitsu is a unit of Palo Alto, California-based startup Cooliris, which has raised $28 million from big venture capital names such as Kleiner Perkins Caufield & Byers, DAG Ventures and The Westly Group.

Cooliris could not be immediately reached for comment.

The company started off as a service to view photo and video content on the Web in a more visually appealing "3D Wall" but branched out to start Adjitsu and a photo sharing app called Liveshare.

Adjistu, which was spun off into a separate unit last December, has been seeing a lot of interest from both advertisers and ad networks, and growing at a rapid pace, the company had said last month.