More than 1,200 employees at the world's leading AI labs, including senior executives, have signed a statement asking the U.S. government to help build the tools needed to slow down AI development if it ever becomes necessary. "Having so many staff from different companies come together in agreement on this point is striking," Tyler Johnston, founder of the Midas Project, an AI watchdog group, told Fortune. It specifically calls out the risks around AI systems that start to design their own successors faster than anyone can understand or control them. "Having talked to many of the people who signed the letter, they don't want a pause," Peter Wildeford, head of policy at the AI Policy Network, told Fortune. The letter comes in the wake of a security breach that has rattled the AI industry.