Nokia said on Monday it is buying U.S. cellphone screen advertising firm Enpocket as the world's top handset maker pushes into a market which is seen ballooning in coming years.

After a slow start, mobile companies are making moves into the potentially lucrative market, helped by new technologies and the spread of more advanced phones.

This is a very interesting move. It gives a clear picture of the speed in which Nokia's new organization is expanding into software and services, said eQ analyst Jari Honko.

Nokia shares rose 0.8 percent to trade at 24.53 euros by 0946 GMT and were the top European blue-chip gainers compared with a 1.7 percent loss for the DJ Stoxx 50.

Nokia did not disclose financial details of the deal which is expected to close in the fourth quarter.

Boston-based Enpocket employs 120 staff and its clients include Vodafone, Pepsi, Telefonica, BT, Sprint and MasterCard.

Nokia said it believes mobile advertising will be an important element in monetizing consumer Internet services.

The Finland-based company unveiled a wide push into mobile consumer Internet services last month, unveiling its new Ovi service, which will combine a new digital music store and a gaming service with its navigation offering.

Effective interactive advertising on the mobile device can create tremendous value for the mobile industry while bringing new Internet services to people around the world, Enpocket President Mike Baker said in a statement.

Strategy Analytics, one of the most cautious forecasters on mobile advertising market growth, has projected global mobile advertising market will reach $574 million this year and grow almost three-fold by 2010.

In addition to media firms and telecom operators, Internet players Google Inc and Yahoo Inc are also keen to have a piece of the growing pie.