Former Treasury Secretary Paul O'Neill has denied allegations he used secret documents to support criticisms of the Bush administration made in a new book.
O'Neill has been out of the administration for more than a year
Mr O'Neill told CBS television that the Treasury Department's chief legal counsel allowed him to take the documents after he asked permission.
On Monday the department called for a probe into whether Mr O'Neill had leaked secret government documents.
Mr O'Neill was sacked from the administration in December 2002.
The book, called The Price of Loyalty and written by former journalist Ron Suskind, details the inner workings of the Bush administration.
Mr O'Neill, who gave thousands of documents to Mr Suskind for research purposes, has made several criticisms of the US president and his colleagues in interviews to promote the book.
In an interview with CBS's 60 Minutes news programme, he accused Mr Bush of planning for an invasion of Iraq within days of coming to office.
The US president was looking for an excuse to oust Saddam Hussein, Mr O'Neill added.
He said that, as a member of the US president's national security team, he never saw any evidence of Iraqi weapons of mass destruction.
And he gave an unflattering account of Mr Bush's leadership style in the interview, saying that at cabinet meetings the president was like a blind man in a room full of deaf people.
The US Department of the Treasury has asked its inspector general to see Mr O'Neill's appearance on the 60 Minutes programme violated disclosure laws.
But on Tuesday Mr O'Neill told NBC's Today show that he had asked the department's chief legal counsel for the documents "that are OK for me to have".
Rumsfeld criticised O'Neill's portrayal of the US president
The counsel then sent him several computer disks with around 19,000 documents on them, which he passed on to Mr Suskind without opening, he said.
He also told the programme that 60 Minutes showed only a cover sheet from a document - not any secret material.
Despite the controversy, Mr O'Neill said he did not think the probe was a move by the Bush administration to silence him.
"If I were secretary of the treasury and these circumstances occurred, I would have asked the inspector general to look into it," he said.
'Night and day'
On Tuesday US Defence Secretary Donald Rumsfeld said he spoke to Mr O'Neill twice after hearing he planned to write a book on the administration but said he did not try to prevent him from writing it.
He said what he had heard about the book was "so different from my experience in this
administration. It is just dramatic. It's night and day".
He also criticised Mr O'Neill's portrayal of the US president.
Analysts say that despite measured responses from senior Bush officials behind the scenes the administration is furious at Mr O'Neill's comments.
Mr O'Neill was sacked from the US Government after nearly two years in his position over differences with the Bush administration.