The Turkish Prime Minister, Recep Tayyip Erdogan, has told the BBC that he believes Iran has no intention of developing nuclear weapons.
Mr Erdogan said he was confident Iran's nuclear programme was for civilian purposes only and described President Mahmoud Ahmadinejad as a "friend".
"I told him I don't want to see nuclear weapons in the region," he added.
Meanwhile, a top US general has said intelligence suggests Iran will not be able to build a nuclear bomb this year.
Gen David Petraeus, the head of US Central Command, said Tehran's weapon development programme appeared to have suffered delays.
"It has, thankfully, slid to the right a bit and it is not this calendar year, I don't think," he told a Senate committee hearing, according to the Reuters news agency.
Experts believe that Iran could enrich enough uranium for a bomb within a few months. However, it has apparently not yet mastered the technology of making a nuclear warhead.
'Manipulating the facts'
In an interview with the BBC's Nik Gowing, Mr Erdogan said he believed it was Iran's "most natural right" to develop a nuclear programme for civilian purposes.
It was, he added, "unfair" of nuclear-armed countries to "manipulate the facts" about Turkey's neighbour while at the same time not telling Israel to dispose of its nuclear weapons.
"Countries with nuclear weapons are not in a position to turn to another country and say: 'You are not supposed to produce nuclear weapons,'" he said.
"Iran has consistently spoken of the fact that it is seeking to use nuclear energy for civilian purposes and that they are using uranium enrichment programmes for civilian purposes only."
"That is what Mr Ahmadinejad has told me many times before."
Mr Erdogan said he had personally warned the Iranian president about the risks of nuclear conflict in the Middle East.
"I told him I don't want to see nuclear weapons in the region, and Mr Ahmadinejad told me that they do not have an intention to produce nuclear weapons."
In February, the International Atomic Energy Agency (IAEA) said in a report that Iran's refusal to co-operate and answer questions about its nuclear programme raised concerns about the possible existence of "past or current undisclosed activities related to the development of a nuclear payload for a missile."
It also confirmed that Iran had produced 20% enriched uranium.
Tehran says it needs the more highly-enriched uranium for a research reactor producing medical isotopes, but Western powers fear it is heading towards enriching uranium to the 90% required for a weapon.