WASHINGTON » President Barack Obama and Chinese President Xi Jinping promoted new agreements Friday on cybersecurity and climate that they said could yield breakthroughs for their nations.

The leaders promised to help each other investigate and prevent cyberattacks and pledged not to commit cyberespionage or support the theft of trade secrets.

Xi also announced that China will limit carbon emissions starting in 2017, setting in motion a cap-and-trade program similar to one that Obama pushed for, but has been unable to achieve, in the U.S.

“This is progress. But I have to insist that our work is not yet done,” Obama said during a news conference in the White House Rose Garden, Xi standing at a lectern beside him.

Xi acknowledged other commitments of importance to the United States — alliance with the U.S. on a tough global climate agreement this year, vigilance on Iran’s pledged adherence to the deal over its nuclear program, opposition to North Korean aggression and peaceful activity in disputed waters.

Those accommodations were key to the Obama administration’s agenda: incrementally improving relations with China and keeping up collaboration on shared projects.

Still, the results of Xi’s state visit left open the question of whether tensions had eased after squabbles over cyberhacks that attacked U.S. government and businesses.

U.S. intelligence officials believe China was behind the theft of millions of security-clearance files as well as recent cyberlooting of health insurance and airline records. For decades, Chinese companies, with the assistance of Beijing, have stolen intellectual property from U.S. companies to replicate American products and engineering. In recent months, Chinese officials have denied responsibility for commercial cyberattacks and called reports of Chinese theft of U.S. data “groundless speculation.”

Xi didn’t apologize for any hacking but rather promised that his government will pursue lawbreakers with vigor. Obama implied that he raised the issue strenuously in private.

“It has to stop,” Obama said at the news conference, leveling only an indirect charge of wrongdoing against the Chinese. “The question now is, are words followed by actions? … We will be watching carefully.”

The Treasury Department has drafted possible economic sanctions on Chinese individuals and companies suspected of stealing data from U.S. companies, but the White House has held off on acting punitively, hoping the threat of sanctions will press China to do more to stop the breaches.

To that end, the two leaders agreed to convene high-ranking officials twice a year and establish a hotline to communicate during breaches.

“This is a good and expected step, but we don’t want companies that make up critical infrastructure to think of this as any sort of protection at this point,” Tom Patterson, an executive at information technology company Unisys Corp. said in a telephone interview. “There is a long way to go before there is any sort of treaty that would provide protection.”

“Espionage went on long before there was an Internet and will go on after the Internet has turned to dust — it is incumbent on these companies to better defend themselves,” Patterson said.

Lawmakers immediately questioned China’s pledge. Rep. Adam Schiff of California, the top Democrat on the House Intelligence Committee, said Xi’s commitment not to steal online commercial secrets is long overdue.

“In the past, China has often said the right things and then done very little to implement its commitments,” he said in an interview.

But, he added, “You’ve got to start somewhere, and it’s a start.”

The first of the high-level meetings on combating cybercrime will come this year, the White House said. The attorney general, the secretary of Homeland Security and the director of the FBI will meet with senior Chinese officials.

During the news conference, Xi briefly mentioned climate change, saying China will work with the U.S. ahead of international climate talks in Paris in December to push for “important progress” at the summit.

When it comes to cutting carbon emissions, Xi is under mounting domestic pressure to address choking smog, curb energy demand and shift China’s economy away from high-polluting manufacturing toward service industries. In 2008, China surpassed the U.S. as the largest global emitter of carbon dioxide.

Last November, Obama and Xi reached a landmark agreement on behalf of their countries, the world’s two biggest polluters, to cut carbon emissions beyond 2020. Critics have questioned how realistic the goals are, but the Obama administration has defended them as important steps nonetheless.

Obama is trying to cement an elusive legacy on environmental issues and has pressed major polluters including China to agree to substantial cuts on carbon emissions.

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(Staff writer Julie Makinen in Beijing contributed to this report.)