The Iranian nuclear scientist who says he was abducted a year ago by CIA agents was an informant for the intelligence agency inside Iran for several years, The New York Times reported on Thursday, citing US officials. Shahram Amiri, who turned up at the Iranian Interests Section of the Pakistam Embassy on Tuesday, returned to Tehran early on Thursday, saying he was pressured to lie about Iran's nuclear programme. The United States denied kidnapping Dr Amiri and insisted he had lived freely in the United States. Officials said the scientist described to US intelligence officers details of how a university in Teheran became the covert headquarters for Iran's nuclear efforts, the newspaper reported. While still in Iran, he was also one of the sources for a much-disputed National Intelligence Estimate on Iran's suspected weapons programme, published in 2007, the officials were cited as saying. One official said Dr Amiri provided 'significant, original' information about secret aspects of his country's nuclear program, according to the newspaper. The US officials told the newspaper that at some point while working as a secret informant, Dr Amiri visited Saudi Arabia, where the CIA arranged to spirit him out of that country. Dr Amiri eventually arrived in the United States and settled in Arizona. The Times said it was unclear whether he tried to bring his wife and son with him.