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.

The statement, titled “Pacing the Frontier,” was published Tuesday and has been signed by prominent tech figures including Anthropic CEO Dario Amodei and several of the company’s co-founders, alongside OpenAI chief scientist Jakub Pachocki, Meta chief scientist Shengjia Zhao, and Google DeepMind’s head of AI safety and alignment, Anca Dragan.

The list brings together companies that are normally locked in fierce competition with each other and is a striking statement for an industry under enormous commercial pressure to keep building ever larger and more capable models.

“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. “There are many bitter rivalries and disagreements in the industry, so the fact that there is such strong consensus on this point is a warning that we really ought to pay attention to.”

While the statement does not ask any company to slow down at the moment, it does call on Washington to support an international effort to build the technical and governance tools that would help the world “pace” development. It specially calls out the risks around AI systems that start to design their own successors faster than anyone can understand or control them.