UPDATE 1-Erdogan lauds Iran's positive approach to nuclear talks

* Turk PM visit at time of deteriorating Turkey-Israel ties

* Erdogan has accused West of treating Iran unfairly

* He praises Iran's "positive attitude" in talks with powers (Adds Ahmadinejad, Erdogan quotes on nuclear issue)

TEHRAN, Oct 27 - Turkey backed Iran's 'positive' approach to nuclear negotiations with world powers during a visit by Prime Minister Tayyip Erdogan on Tuesday that may point to a shift in the emphasis of Turkish foreign policy.

Iranian President Mahmoud Ahmadinejad praised Erdogan for his "clear stance against" Israel, Iran's official media said.

Edogan's trip to Iran comes at a times of worsening relations between Turkey and Israel, a process that began with Israel's Gaza offensive in December 2008.

Erdogan has steadily expanded NATO member Turkey's influence in the Middle East since his Islamist-rooted AK Party took power in 2002. His visit to Iran has added to concerns that Ankara may be slowly turning its back on its Western allies and seeking to regain its status as a regional power in the Middle East.

The Turkish prime minister backed Iran's "right to peaceful nuclear energy," Iranian state television reported.

"This is an energy project with peaceful, humanitarian purposes," he told reporters travelling with him in Iran.

Erdogan said Iran, in talks with six world powers in Geneva on Oct. 1, showed it "can work with" Russia and the United States on uranium enrichment. "If their positive attitude is answered with a positive attitude, this will bring forward the process in the positive direction," he said.

Earlier this week, Erdogan accused the West of treating Iran unfairly over its nuclear programme, in comments that come as world powers await Tehran's response to a U.N.-drafted plan which would require it to send potential nuclear fuel abroad.

ISRAEL

In a swipe at Israel, Ahmadinejad told Erdogan, according to IRNA news agency: "When an illegal regime has atomic weapons, it is not possible to prevent others from having access to peaceful nuclear energy."

Israel is believed to be the only nuclear-armed Middle East state. Iran rejects Western accusations that it is seeking to develop nuclear bombs and says its atomic activities are aimed at generating electricity.

Ahmadinejad, who has repeatedly predicted Israel's imminent demise, blamed foreign states for regional problems and called for an expansion of Tehran-Ankara ties. His comments appeared aimed at the West, including Turkey's ally the United States.

"The more regional countries expand their ties ... the more they can remove their problems and limit the ill-wishers which have plots against them," he told Erdogan.

Erdogan's visit to Iran comes two weeks after Turkey barred Israel from a NATO exercise, a decision that angered Israel and prompted rare criticism from the United States.

Diplomatic relations between Turkey and Israel have suffered since Israel's offensive in the Gaza Strip, in which Erdogan accused Israel of committing crimes against humanity.

Turkey, a mainly Muslim country seeking European Union membership, says it is willing to mediate in the dispute.

Bilateral Iran-Turkey trade reached $7 billion in 2008. Turkey's Energy Minister Taner Yildiz told Reuters last week he hoped the two countries could finalise a $3.5 billion deal to develop part of the world's largest gas field in Iran.

Iran is Turkey's second-biggest supplier of natural gas after Russia. Turkey has said that Iranian gas can help the planned Nabucco pipeline to supply Europe and lessen the continent's dependence on Russian deliveries.