Viacom, the world’s largest media group, has cut back its estimates for the full year. The group says that national advertising in the US is strong, but local advertising is not up to expectations.

The New York-based company,owner of CBS and MTV, now expects single digit growth in revenues and operating income for the full year.

But Viacom still hopes for record revenues, operating income and earnings per share as well as strong growth during 2004, when it hopes to gain from the improved US economy, presidential election advertising and Super Bowl ads.