The chief of US intelligence has rejected criticism over how spy agencies responded to a deadly attack on diplomats in Libya and said there was no clear warning before the onslaught. Pushing back against allegations from Republican lawmakers, Director of National Intelligence James Clapper suggested on Tuesday it was naive to believe the government could have quickly arrived at a definitive explanation of last month’s attack on the US consulate in the eastern Libyan city of Benghazi. The veteran intelligence official, appearing at a security conference in Orlando, Florida, voiced frustration with the criticism directed at his spy service, as he recounted reading through media coverage on a flight back from a working trip to Australia. “I flew back to Washington, and I’m reading the media clips about the hapless, hopeless, helpless, inept, incompetent DNI, because I acknowledged publicly that we didn’t instantly have that ‘God’s eye, God’s ear’ certitude about an event as I mentioned earlier,” said Clapper, according to a video of his remarks released by his office. “It kind of made me want to get right back on the plane to Australia.” Clapper said there was no telltale sign of an imminent attack on the US consulate in Benghazi on September 11, when dozens of gunmen laid siege to the compound, killing US ambassador Chris Stevens and three of his staff. “The challenge is always a tactical warning, the exact insights ahead of time that such an attack is going to take place and obviously we did not have that,” Clapper said, answering questions after a speech. “If people don’t behave, emit a behaviour or talk or something else ahead of time to be detected, it’s going to be very hard to predict an exact attack and come up with an exact attack.” President Barack Obama’s administration has come under fire for offering varying accounts of the incident, initially saying it was a “spontaneous” assault ignited by a protest against a film that denigrated Islam and its Prophet Mohammed. Clapper quoted at length from an October 1 commentary by former CIA officer Paul Pillar that hit out at critiques of the handling of the Benghazi attack as ill-informed, counter-productive and irresponsible. The article published in The National Interest journal “deeply resonated with me”, said Clapper, adding that it carried important lessons for the government, lawmakers and the media. Pillar wrote that hindsight was “cheap” in a case like Benghazi, diplomacy was inherently dangerous work, intelligence information usually evolves after such an assault and “total security” was impossible in any setting. “A demand for an explanation that is quick, definite and unchanging reflects a naive expectation – or in the present case, irresponsible politicking,” Pillar added. Clapper’s comments came as the State Department countered charges of security lapses in Libya, with officials describing a fierce attack that erupted without warning. State Department officials will face a grilling on Wednesday at a congressional hearing into the Benghazi attack, which has become fodder for the US presidential campaign.