BBC News reports the attackers gained entry to the academy wearing police uniforms.
Early tweets flagged up news resources for other Twitter users, and made comments on the ongoing situation.
@tahiriqbal (Lahore, Pakistan) just came to knw abt the attack on Police Academy in #Lahore. We'll never get control of Terrorists as long as we've currpt politicians.
@chinchinchoo live coverage of lahore police academy hostages http://tinyurl.com/ccx5lc
@paknews (Pakistan) Gun battle at Pakistan police academy http://twurl.nl/kcdlf8