The governor's move came 11 days after three Pittsburgh police officers were killed by a man with an AK-47.
"Time and time again, our police are finding themselves outgunned," he said at a news conference Wednesday. "They are finding themselves with less firepower than the criminals they are trying to bring to justice."
Rendell also called on state lawmakers to pass "simple" gun-control measures, The Philadelphia Inquirer said.
Congress approved a ban on the sale and possession of assault weapons but it expired in September 2004. Last month, 65 House Democrats announced that they would oppose reinstating the ban.