China is continuing to conduct cyber espionage operations against the United States, and Beijing’s commitment to a U.S.-China cyber agreement is questionable, the director of national intelligence told Congress on Tuesday.

“China continues cyber espionage against the United States,” James Clapper, the director, testified during an annual threat briefing to the Senate Armed Services Committee.

“Whether China’s commitment of last September moderates its economic espionage remains to be seen,” he added.

Clapper identified potential cyber attacks against critical infrastructure and advancing cyber warfare capabilities in nations such as China, Russia, North Korea and Iran as the among the most serious U.S. national security threats.

“China continues to have success in cyber espionage against the U.S. government, our allies, and U.S. companies,” Clapper said in a prepared statement.

Intelligence agencies are monitoring Beijing’s compliance with a September agreement not to conduct commercial cyber espionage. However, Clapper stated that since the agreement, private sector cyber security analysts “identified limited ongoing cyber activity from China but have not verified state sponsorship or the use of exfiltrated data for commercial gain.”

Clapper sidestepped policy questions about what to do about large-scale Chinese cyber attacks. The role of U.S. intelligence agencies, he said, is to inform national leaders of the problem and suggest ways to stop cyber attacks.

China last year was linked to the large-scale theft of some 80 million Americans’ health care records, and also was blamed for pilfering sensitive personal data on 22 million federal workers during cyber attacks on Office of Personnel Management networks. The Obama administration took no action against China for the attacks.