Exclusive Details

11:45 AM PT -- Law enforcement sources now tell us they've already seen more than a thousand images of "child sexual exploitation" on Salling's computer. Cops also seized other electronic devices, including tablets and cellphones. We're also told he lives alone, which will make it hard to argue someone else put the images in the computer.

Our sources say when cops arrived to search the home, Salling was "shocked."

We're also told Salling has already lawyered up.

"Glee" star Mark Salling has just been arrested for possessing child porn ... TMZ has confirmed.

We're told the LAPD's Internet Crimes Against Children Task Force obtained a warrant and served it Tuesday morning, as first reported by the TV show "Crime Watch Daily."

We're told cops searched Salling's computer at his Sunland home and found hundreds of images. At the time of this post, Salling is being taken to the police station for booking.

Law enforcement sources say the images they captured from Salling's computer were children ... significantly younger than 15 and 16 year olds.

Our sources say an ex-girlfriend of Salling's tipped off cops and they investigated before the raid to make sure it wasn't a revenge allegation.

Salling has had his share of legal problems. In 2013 he was sued by a woman who claimed he committed sexual battery on her by forcing sex without a condom. Salling denied the charge and the case settled.