Yuval Steinitz is not impressed. REUTERS/Eduardo Munoz JERUSALEM (Reuters) - Israeli officials said on Saturday they were not surprised by allegations the United States and Britain had spied on the country's leaders and played down the importance of any information its allies may have gleaned.

Leaked documents from former U.S. National Security Agency (NSA) contractor Edward Snowden published on Friday showed the NSA and its British counterpart GCHQ had in 2009 targeted an email address listed as belonging to the Israeli prime minister and monitored emails of senior defense officials.

"Our working assumption is that not only Arab states but also world powers, including friendly ones, try to follow us," Strategic Affairs Minister Yuval Steinitz told Israel's Channel 2 television.

Israel therefore takes the necessary precautions, he said, and secret information is never transmitted over "regular phones and email systems".

The office of Ehud Olmert, who at the time was Israel's prime minister, said in a statement that the reports, if accurate, referred to a public email address.

"The chances that security or intelligence damage was caused from the breaking in to this email address were minuscule," the statement said.

Steinitz emphasized the close intelligence ties between Israel and the two countries.

(Reporting by Ari Rabinovitch; editing by Andrew Roche)