Defense Secretary Leon Panetta signed an order Friday to send two Patriot missile batteries to Turkey to protect it from rounds crossing the border from Syria. The order includes 400 American personnel to operate the batteries. Pentagon spokesman George Little acknowledged that the move was a symbolic show of force. “The purpose of this deployment is to signal very strongly that the United States, working closely with our NATO allies, is going to support the defense of Turkey, especially with potential threats emanating from Syria,” Little told reporters before Panetta landed on an unannounced visit to Turkey. He added that he expected the deployment to occur “in the coming weeks.” Little said the missiles and personnel would remain in place for “an unspecified period of time.” The Assad regime losing control of Syria to rebels, his ally Russia says. The 20-month-old uprising against Syrian President Bashar Assad has turned increasingly bloody and heavy fighting has often erupted along Syria’s northern border with Turkey, which is supporting the Syrian opposition. The Patriot system is designed to intercept aircraft or missiles. Turkey has asked NATO to deploy Patriot missiles to shore up its 560-mile border, where it fears security may crumble as the Syrian army fights harder to contain the rebels — who have enjoyed sanctuary in Turkey.