President Barack Obama announced on Friday that he had reached a "common understanding" with Chinese President Xi Jinping on curbing economic cyber-espionage, but threatened to impose U.S. sanctions on Chinese hackers who persist with cybercrimes.

The two leaders also unveiled a deal to build on a landmark emissions agreement struck last year, outlining new steps they will take to deliver on pledges to slash their greenhouse gas emissions.

Speaking after White House talks during Xi's first U.S. state visit, Obama quickly homed in on the thorniest dispute between the world's two biggest economies — growing U.S. complaints about Chinese hacking of government and corporate databases, and the suspicion in Washington that Beijing is sometimes behind it.