In an apparent violation of U.S. policy, Peace Corps volunteers and a Fulbright scholar were asked by a U.S. Embassy official in Bolivia "to basically spy" on Cubans and Venezuelans in the country, according to Peace Corps personnel and the Fulbright scholar involved.

"I was told to provide the names, addresses and activities of any Venezuelan or Cuban doctors or field workers I come across during my time here," Fulbright scholar John Alexander van Schaick told ABCNews.com in an interview in La Paz.

Van Schaick's account matches that of Peace Corps members and staff who claim that last July their entire group of new volunteers was instructed by the same U.S. Embassy official in Bolivia to report on Cuban and Venezuelan nationals.

The State Department says any such request was "in error" and a violation of long-standing U.S. policy which prohibits the use of Peace Corps personnel or Fulbright scholars for intelligence purposes.

"We take this very seriously and want to stress this is not in any way our policy," a senior State Department official told ABCNews.com.

The Fulbright scholar van Schaick, a 2006 Rutgers University graduate, says the request came at a mandatory orientation and security briefing meeting with Assistant Regional Security Officer Vincent Cooper at the embassy on the morning of Nov. 5, 2007.

According to van Schaick, the request for information gathering "surfaced casually" halfway through Cooper's 30-minute, one-on-one briefing, which initially dealt with helpful tips about life and security concerns in Bolivia.

"He said, 'We know the Venezuelans and Cubans are here, and we want to keep tabs on them,'" said van Schaick who recalls feeling "appalled" at the comment.