(Recasts, adds quotes)
DUBAI, April 9 (Reuters) - Supreme leader Ayatollah Ali Khamenei said on Wednesday he had authorised nuclear talks with world powers including arch-foe the United States just to prove Iran's peaceful intentions, but Tehran would not be bullied and would not stop atomic research.
He added in remarks to nuclear scientists that Iran should continue the discussions to end a dispute over nuclear work the West fears is aimed at developing a bomb, but Iran's negotiators should not cede any gains made by its nuclear programme.
"Americans are well aware we are not after nuclear weapons, but they still raise the charges every now and then to keep up the anti-Iran hype," Khamenei told a group of nuclear scientists and officials who gathered to mark Iran's "Nuclear Technology Day," an important event in Iranian calendar.
"That's why I agreed to the government's initiative to negotiate, just to break the hype and expose the truth to world opinion," he said, referring to moderate President Hassan Rouhani's diplomatic overture to the West after his landslide election last June.
Khamenei, who wields near absolute power in Iran, warned however that there was a limit to how far the Islamic Republic would go to satisfy its adversaries on the nuclear issue.
"No, Our pursuit of nuclear science will never halt. We will not cede any of our gains in nuclear research and development and our negotiators must not allow the other side to bully Iran," he said, as quoted by the official IRNA news agency.
"The decision to negotiate doesn't mean we will backtrack on the issue."
However, the Iranian clerical leader reaffirmed support for diplomacy as a means to settle the long-running nuclear dispute which has cost Iran economically ruinous sanctions.
Khamenei spoke as Iranian negotiators and major powers - the United States, Russia, China, Britain, France and Germany - met for the second of two days of talks in Vienna to try to clear the way for a long-term accord on Tehran's nuclear work, although diplomats said "significant gaps remained to be bridged.
Iran denies accusations its nuclear programme is intended to obtain nuclear weapons capability. It wants an end to sanctions and to regain what it sees as its rightful place as a leading regional power.
(Reporting by Mehrdad Balali; Writing by William Maclean; Editing by Mark Heinrich)