But Erdogan took issue with a vote by the International Atomic Energy Agency last week censuring Iran after President Mahmoud Ahmadinejad rejected a Western offer to enrich uranium to fuel a research reactor outside the country.
"I believe that was a very rushed process because certain steps could be taken in a more consultative fashion," Erdogan said at a press conference, speaking through an interpreter.
Erdogan previously raised concerns in Washington in October when he accused the West of treating Iran unfairly by demanding that it halt what it says is a peaceful nuclear programs, while not demanding the same of nuclear-armed countries in the region, an allusion to Israel.
His position appeared unchanged after his talks with Obama Monday despite Iranian threats to build 10 more uranium enrichment facilities to produce more highly enriched fissile material that the United States fears will be used for nuclear weapons.
"We believe that relations between Iran and the rest of the world can only be improved through diplomacy, and Turkey can play a role in that regard," he said.
"We do not want a country in our region to possess a nuclear weapon, and we want countries that already possess nuclear weapons to be rid of them. This is our thesis that we abide by."
But he said Turkey had no problem with Iran's nuclear program so long as it was for peaceful, civilian purposes.
"But if for the formation of WMDs (weapons of mass destruction) or chemical weapons, those problems can only be solved through diplomatic means," he said.
"Turkey can play the role of negotiator or a mediator and this is the only information that we shared with President Obama."
He said Turkey had contacts and a positive relationship with Iran that could be useful.
Earlier at the White House, Obama poured effusive praise on Turkey as a NATO ally and said he believed "it can be an important player in trying to move Iran" toward abiding by international norms and atomic rules.
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