Documents leaked on Friday by former US National Security Agency contractor Edward Snowden showed the NSA and its British counterpart GCHQ had in 2009 targeted an email address listed as belonging to then-Israeli Prime Minister Ehud Olmert and monitored emails of senior defense officials.
Reports also said that spy organizations rented an apartment next to then Defense Minister Ehud Barak to eavesdrop on his calls.
"With regard to things published in the past few days, I have asked for an examination of the matter," Netanyahu said in broadcast remarks, in a clear reference to the alleged espionage.
He did not elaborate on whether Israel intended to ask Washington for clarifications.
"In the close ties between Israel and the United States, there are things that must not be done and that are not acceptable to us," Netanyahu said, speaking during a Likud party faction meeting.
On Sunday, several Israeli cabinet members and lawmakers said disclosure of US spying on Israel was an opportunity to press Washington to free jailed Israeli agent Jonathan Pollard.
Pollard was sentenced to a life term in 1987 in the United States for spying for Israel. A succession of US presidents have spurned Israeli calls for his pardon.
In what appeared to be an attempt to calm the clamor, Netanyahu said on Sunday that Israel had constantly sought Pollard's release and did not need any "special occasion" to discuss his case with Washington: "I just met with Esther Pollard and updated her on our unceasing efforts to free Jonathan."
Netanyahu added, "He should have been released long ago. This is understood by everyone here and I believe is understood by a growing number of people in the United States."
Israeli officials have played down the importance of any information the United States may have gleaned from its alleged espionage activities.
Strategic Affairs Minister Yuval Steinitz said Israel had always assumed that even its allies spied on it. A statement issued by Olmert's office, said the reports, if accurate, referred to a public email address and that chances that any security or intelligence damage had been caused were minuscule.
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