The government spokesman was responding to this week's arrest in the United States of a Defense Department weapons system analyst and three others in two separate espionage-related cases.

"The so-called accusation against China on the issue of espionage is totally groundless and has ulterior motives," Xinhua quoted Chinese Foreign Ministry spokesman Liu Jianchao as saying.

"We urged the United States to abandon its Cold War thinking and stop groundless accusations and instead contribute to increasing mutual trust and friendship between our two peoples," Liu said.