A chorus of congressional lawmakers is demanding that the Obama administration respond to what U.S. intelligence agencies say is an aggressive Chinese campaign of cyber attacks designed to steal commercial and defense secrets from U.S. companies.

At a hearing Tuesday, Rep. Mike Rogers, a Michigan Republican who chairs the House Intelligence Committee, accused the Chinese government of engaging in a "predatory" policy of cyber theft that he said has reached "an intolerable level."

Dianne Feinstein, a California Democrat who chairs the Senate Intelligence Committee, said in a statement that she believed "a significant portion" of cyber intrusions on U.S. companies "emanate from China."

She called on the administration to pursue the matter with Beijing "to bring these rampant cyber thefts and attacks under control."

U.S. authorities have accused China of sponsoring cyber espionage in the past. Tommy Vietor, spokesman for the National Security Council, declined to comment.

In recent years, the U.S. has created cyber-defense units in the FBI, the Department of Homeland Security and the Defense Department. The U.S. role in offensive cyber attacks around the globe is little understood, but the National Security Agency, the Pentagon's eavesdropping arm, is responsible for code breaking and communications intercepts involving foreign targets.

The U.S. should confront Beijing, Rogers said by establishing international rules against stealing corporate secrets through cyber attacks.

Rogers said China sponsors teams of hackers who infiltrate computer networks and siphon commercial secrets from U.S. companies to benefit Chinese companies.

"I don't believe that there is a precedent in history for such a massive and sustained intelligence effort by a government to blatantly steal commercial data and intellectual property," he said at the hearing, adding later, "I feel very comfortable saying that Chinese nation state activities have led to the exfiltration of intellectual property at a staggering rate."

"I step back in awe at the breadth, depth, sophistication and persistence of the Chinese espionage effort against the United States of America," Michael Hayden, the former director of the CIA and NSA, said at the hearing.

China has repeatedly denied sponsoring cyber attacks. The Chinese Embassy in Washington did not respond to interview requests.

The National Security Agency cannot share classified intelligence with private companies, even if they are subject to an attack. And companies that are targeted often do not disclose attacks against them.

In some recent cases, hackers have tricked corporate users into clicking on computer links that open their computer networks to intrusion, said Arthur Coviello, executive chairman of RSA, the cyber-security division of information technology firm EMC, based in Hopkinton, Mass.

RSA disclosed in March that an attack compromised an authentication system used by defense contractors to protect their data. Coviello did not blame China at the hearing, but a report in the September issue of Vanity Fair magazine said experts working for U.S. intelligence identified China as the culprit.

The U.S. government does not spy on behalf of individual companies or industries, current and former officials say.

The Chinese government, they say, conducts economic espionage to gain technology developed in the West.

ken.dilanian@latimes.com