The Vermont senator responded to Clinton's remarks on gun violence.
She accused Sanders of using a straw-man argument to explain his record on guns.
Niall Stanage 04/11/16 05:54 PM EDT
"He did the smart thing and got out of the firing line," said one strategist.
The ad features several high-profile social activists.
The Cowboy State gives Sanders seven wins in the last eight contests.
The campaign data show Sanders with 1,088 pledged delegates and lists 38 superdelegates on board.
"I have not forgotten where I was born and that is Brooklyn," he told supporters.
“There is zero chance that @HillaryClinton doesn't clinch the nomination by June,” Brian Fallon said.
Sanders won Wisconsin's primary by a double-digit margin on Tuesday.
"There is not even the remotest chance that is going to happen."