“Our diplomats are just that, diplomats,” he said. “They represent our country around the world and engage openly and transparently with representatives of foreign governments and civil society. Through this process, they collect information that shapes our policies and actions. This is what diplomats, from our country and other countries, have done for hundreds of years.”

The cables, sent to embassies in the Middle East, Eastern Europe, Latin America and the United States mission to the United Nations, provide no evidence that American diplomats are actively trying to steal the secrets of foreign countries, work that is traditionally the preserve of spy agencies. While the State Department has long provided information about foreign officials’ duties to the Central Intelligence Agency to help build biographical profiles, the more intrusive personal information diplomats are now being asked to gather could be used by the National Security Agency for data mining and surveillance operations. A frequent-flier number, for example, could be used to track the travel plans of foreign officials.

Several of the cables also asked diplomats for details about the telecommunications networks supporting foreign militaries and intelligence agencies.

The United States regularly puts undercover intelligence officers in countries posing as diplomats, but a vast majority of diplomats are not spies. Several retired ambassadors, told about the information-gathering assignments disclosed in the cables, expressed concern that State Department employees abroad could routinely come under suspicion of spying and find it difficult to do their work or even risk expulsion.

Ronald E. Neumann, a former American ambassador to Afghanistan, Algeria and Bahrain, said that Washington was constantly sending requests for voluminous information about foreign countries. But he said he was puzzled about why Foreign Service officers  who are not trained in clandestine collection methods  would be asked to gather information like credit card numbers.