WASHINGTON  - The CIA’s internal watchdog is investigating allegations that the agency improperly spied on Senate staffers probing secret details of a now-defunct interrogation programme.

Senator Dianne Feinstein acknowledged Wednesday the existence of the probe, which highlights a rare public clash between lawmakers on the Senate Intelligence Committee she chairs and the US espionage community it oversees. “The IG is taking a look at the situation,” Feinstein told reporters, referring to the Central Intelligence Agency’s inspector general, after a New York Times report exposed Capitol Hill anger at CIA staffers’ behavior.

According to the Times, the probe began when members of Congress complained that agency employees were inappropriately monitoring intelligence committee staffers. The paper cited an official, who insisted on anonymity because the investigation was ongoing, as saying CIA officers managed to gain access to computer networks used by committee staffers probing the agency’s detention and interrogation programme.

The staffers had spent years researching and writing a 6,000-page bipartisan report that was highly critical of the programme, which began under president George W. Bush. In December 2012, when the report was approved by her committee, Feinstein described the creation of clandestine “black sites” and the use of enhanced interrogation techniques such as waterboarding as “terrible mistakes.”

The McClatchy news service reported that the inspector general’s office has asked the Justice Department to investigate the case.  But CIA Director John Brennan vehemently defended the spy agency and blasted some lawmakers for what he called unfounded allegations.

“I am deeply dismayed that some members of the Senate have decided to make spurious allegations about CIA actions that are wholly unsupported by the facts,” Brennan said in a bluntly worded statement. “I am very confident that the appropriate authorities reviewing this matter will determine where wrongdoing, if any, occurred in either the executive branch or legislative branch.”

Meanwhile, the US military carried out freedom of navigation operations challenging the maritime claims of China, Iran and 10 other countries last year, asserting its transit rights in defiance of efforts to restrict passage, a Pentagon report said on Thursday.

The Defence Department’s annual Freedom of Navigation Report to Congress for the 2013 fiscal year showed the US military targeted not only countries such as Iran, with whom it has no formal relations, but treaty allies such as the Philippines, too.

The US military conducted multiple operations targeting China over what Washington believes are “excessive” claims about its maritime boundaries and its effort to force foreign warships to obtain permission before peacefully transiting its territorial seas.

US operations challenging Iran were aimed at rejecting Tehran’s effort to restrict the Strait of Hormuz to ships from nations that have signed the UN Convention on the Law of the Sea, an accord the United States has not formally adopted.

The report covers activity in the 2013 fiscal year that ended Sept. 30, before the latest tensions over a near mishap between US and Chinese warships in the South China Sea and Beijing’s declaration of an air Defence identification zone over the East China Sea, which Washington rejected.