American National Security Agency (NSA) documents published by US and British newspapers in recent weeks reveal both the extent of American-Israeli intelligence co-operation but also the efforts by the Americans to keep tabs on Israeli operations.

The latest tranche of documents, taken by former NSA employee Edward Snowden before he fled to Hong Kong and then Moscow, were published on Friday in the New York Times, which has worked in collaboration the Guardian on the revelations.

The documents included details of NSA tracking of Israeli weapons systems including Israel Air Force (IAF) drones and strategic missiles. Among the Israeli weapons spied on by the NSA was the “Black Sparrow” target-missile, which is used by the IAF to simulate attacks involving incoming long-range Iranian Shahab-3 missiles.

While no official comment was forthcoming from the Israeli government on the revelations, former Israeli security officials speaking off the record were not surprised.

The assumption within Israel’s defence establishment is that both the NSA and the CIA have been directed by the White House to collect information on Israel’s intentions in talks with the Palestinians and any undisclosed plans to attack Iran’s nuclear installations.

According to a summary of the US intelligence budget also obtained by Mr Snowden and published in August by the Washington Post, Israel is a priority strategic intelligence target, along with Russia, Iran, China and Cuba.

Uniquely, Israel is seen by the American intelligence community as a country that conducts its own spying in the US but at the same time is allowed to share “raw SIGINT” (unredacted) data gathered by the NSA and the IDF’s Unit 8200.

While some of the documents contain complaints by US intelligence professionals that Israel gets more out of the agreement than the US, one senior Israeli defence official said recently: “We give the Americans the crown jewels of intelligence.”