The U.S. National Security Agency shared unredacted private communications from Americans – particularly Arab-Americans – with a key Israeli military-intelligence unit, an author and professor wrote.

In a New York Times op-ed piece, James Bamford said that he'd met this summer with Edward Snowden, the former NSA contractor who leaked thousands of classified documents.

Snowden found that the data NSA was passing to Israel's Unit 8200 included IDs for who was calling whom.

Snowden said that the callers' relatives in Israel and the territories could become targets based on the data, Bamford wrote in the Tuesday op-ed. When NSA shares information with other countries, it normally removes that identifying data, Bamford wrote.

Unit 8200 is the largest unit in the Israel Defense Forces and one of the military's most prestigious divisions. It focuses on signals intelligence, or communications eavesdropping.

A week ago 43 former members of Unit 8200, including some officers, wrote an open letter to Prime Minister Benjamin Netanyahu and top military officials, saying they would refuse to do reserve service because of Israel's `political persecution' of the Palestinians.

The signatories said the information that is gathered and stored in the army’s systems “harms innocent people. It is used for political persecution and to create divisions within Palestinian society by recruiting collaborators and driving parts of Palestinian society against itself.”

Bamford argued that Americans should be concerned that NSA is providing information to be used not to ensure security but "simply to pursue political agendas."

And he said the American public should be concerned that NSA might do the same sort of monitoring within the U.S. – and may already be doing so.