President Abdullah Gul said Turkey backs a negotiated settlement of the Iran nuclear issue by dialogue, as he prepared to travel to Tehran on his maiden official visit, state media reported.

"Turkey wants a solution for Iran's nuclear issue through negotiations and dialogue," Gul told Iran's official news agency IRNA in what it said was an exclusive interview ahead of the scheduled trip.

Gul begins a three-day visit on Monday which will see him meeting top Iranian officials, including his counterpart Mahmoud Ahmadinejad. He will also visit the cities of Tabriz and Isfahan.

"Iran is signatory to the Non-Proliferation Treaty and a member of the International Atomic Energy Agency. Thus, Iran's nuclear issue should be solved through negotiation and Turkey will continue to facilitate this," Gul said.

Turkey's ties with its eastern neighbour have markedly improved since Ankara's current Islamist-rooted government came to power in 2002.

Last month, Turkey hosted talks between Iran and six world powers aimed at allaying Western suspicions that Tehran is secretly developing nuclear weapons, but no progress was achieved.

In June, Turkey -- then a non-permanent member of the UN Security Council -- irked the United States when it voted against fresh sanctions the body approved against Iran, arguing that a nuclear fuel swap deal it had negotiated together with Brazil the previous month should be given a chance.

Gul also places importance on the economic ties between Ankara and Tehran.

"Both nations want to expand ties in all aspects," he said.

"We will discuss political, economic and cultural issues. Many Turkish investors and businessmen are travelling with me and we will hold joint economic commissions."

Iranian and Turish officials have said they want to increase trade between the two countries to $30 billion by 2015 from the present $10 billion.

Turkey's improving ties with Iran, coupled with a deep crisis in its relations with long-time ally Israel, have sparked concern that NATO's sole Muslim-majority member is sliding away from the West. Ankara strongly denies any policy shift.

Gul said his visit to Tehran was also in response to several trips made by his Iranian counterpart to Ankara.