A NATIONAL PORN conglomerate based in Center City was raided by the FBI, the IRS and local authorities early yesterday, but federal officials remain tight-lipped about what exactly they were seeking.

The feds, carrying search warrants, descended on the corporate offices of National A-1 Advertising, on 7th Street near Chestnut, about 9 a.m., reported AVN.com, an adult-entertainment trade magazine.