China's government must halt economic espionage in cyberspace, U.S. National Security Advisor Susan Rice warned on Monday, days before Chinese President Xi Jinping is due in Washington, D.C., on an official visit.

The issue has become a major thorn in the side of U.S.-China relations in the last year, especially in the wake of the breach of personal information of tens of millions of U.S. government workers at the Office of Personnel Management. The U.S. hasn't publicly accused China of that hack but has done so privately. China denies any involvement.

"This isn’t a mild irritation," Rice said in a speech at George Washington University. "It’s an economic and national security concern to the United States. It puts enormous strain on our bilateral relationship and it is a critical factor in determining the future trajectory of U.S.-China ties."

"Cyber-enabled espionage that targets personal and corporate information for the economic gain of businesses undermines our long-term economic cooperation and it needs to stop," she said.

On Sunday, The New York Times reported the two governments are negotiating what amounts to an arms control treaty for cyberspace and hope to announce it this week.

The deal would call for each country to commit not to be the first to use cyberattacks to disable critical infrastructure such as the telephone network or power grid during peacetime.

High-level talks have been continuing between the two countries in the run up to Xi's state visit, although officials haven't provided details on what is being discussed.

If the New York Times report is correct, the deal between the two governments would be a first step in reducing cyber concerns, but wouldn't address the type of cyber espionage that Rice talked about.

Rice began her speech by speaking about the many areas in which China and the U.S. have cooperated and the importance each holds to the other in global trade, but then turned to the issues that are current concerns of the U.S.

While underlining the importance of good relations between the world's two biggest economies, Rice highlighted cyberespionage, Internet freedom, human rights, maritime disputes in East Asia and intellectual property concerns.

"Everyone has to play by the same rules regardless of size or power," she said. "That's the way everyone can compete and be treated equally."