"No deal", said Dr Mahathir was quoted as saying in the article based on an interview conducted by video link for The Wall Street Journal CEO Council in Tokyo.
Mahathir told the Wall Street Journal he would be in power for one to two years - before an expected handover to former opposition leader Anwar Ibrahim, who is expected to be released on Wednesday after three years in jail on a sodomy conviction.
Dr Mahathir, who first led the country from 1981 to 2003 under Umno, is now Prime Minister under an agreement with PH that he would eventually hand over power to Mr Anwar, whose Parti Keadilan Rakyat (PKR) has the most MPs in the four-party alliance. Anwar worked from his prison cell to forge a new opposition alliance by ending his two-decade feud with Mahathir, a gamble that paid off when the alliance won May 9 polls and ended the National Front's 60-year grip on power.
When asked if he might be willing to cut a deal to spare Najib, if he were to offer information that can recover part of the US$4.5bil (RM18.19bil) allegedly lost by 1MDB, Dr Mahathir would only say: "No deal".
As he left the press conference, Dr Mahathir light-heartedly told those present to "reserve" their questions for another time.
"We are slowly getting to the bottom of things and many of our senior officers are volunteering information accompanied, of course, by documents". Numerous senior officials are volunteering information, accompanied of course by documents.
Prime Minister Tun Dr Mahathir Mohamad remained steady when faced with a barrage of questions from the media on his first day back at work as the country's top official. He has also ordered the attorney general who cleared Najib of any wrongdoing in 2016 to go on leave pending an investigation, while the head of the anti-graft body has resigned.
Mahathir has barred Najib and his wife from leaving the country.