A suicide bomb squad killed a police officer and wounded nearly a dozen people in central Turkey on Friday after it drove into a police station and opened fire, reports said.

Three men sped their vehicle into a police station in the city of Kayseri, where they fired weapons before one of the attackers set off a bomb strapped to his body, it said.

Iran rejects Western pressures over its nuclear activities and will never give up its rights, Tehran's chief nuclear negotiator said Thursday ahead crunch talks with world powers in Baghdad next week.

"If we participate in the negotiations... it is because of our resistance (to Western powers). Thanks to our resistance, we have defended the rights of the Iranian people," Saeed Jalili said in a speech broadcast on local television.

Syrian tribes opposed to the embattled regime of Bashar al-Assad said Monday they would join forces in an "Assembly of Tribes," Syrian opposition members and media reported.

"Today we proclaim, as children of all tribes, an Assembly of Tribes," opposition Syrian National Council (SNC) member Mahmut al-Maslat said in a statement read out on behalf of the assembly.

Talks between Iran and six world powers in Istanbul on Tehran's nuclear program, the first in 15 months, began Saturday in a "positive atmosphere," a European Union spokesman said.

"There is a positive atmosphere. ... There is a desire for substantive progress," Michael Mann, spokesman for EU foreign policy chief Catherine Ashton, told reporters.

Iran is to present "new initiatives" at nuclear talks with world powers in Istanbul on the weekend, the official leading the country's negotiating team, Saeed Jalili, said on Wednesday.

"The Iranian delegation will have new initiatives and we hope that the other party will have a constructive approach," he told Iran's Arab-language network al-Alam, without elaborating.

Iran on Monday urged "honesty" at crucial talks with world powers due to be held this week in order to defuse a tense international showdown over its disputed nuclear activities.

"We hope the P5+1 will come to the negotiating table with honesty, and we also will make an honest effort so that both sides reach a win-win conclusion," Foreign Minister Ali Akbar Salehi told the Iranian parliament's website.

World powers will hold a fresh round of nuclear talks with Iran in Istanbul on April 14, a spokesman for European Union foreign policy chief Catherine Ashton said Monday.

"We have agreed to launch talks in Istanbul on April 14," Michael Mann said.

A Syrian government newspaper said on Monday that a weekend meeting in Istanbul of what it called the "Enemies of Syria" was a failure for those seeking to topple President Bashar Assad.

"Despite all the hype, the conference of the 'Enemies of Syria' produced only meager results... showing it was unable to shake Syrians' rejection of foreign intervention," said al-Baath newspaper, mouthpiece of Assad's ruling party by the same name.

An international conference in Istanbul by "Friends of Syria" countries on Sunday urged the United Nations to act to stop the violence and recognized the opposition Syrian National Council as the "legitimate representative of all Syrians," but steered clear of backing opposition appeals for arms to fight the regime clampdown.

In a final declaration, the conference urged Syria mediator Kofi Annan "to determine a timeline for next steps, including a return to the U.N. Security Council, if the killing continues."

Damascus on Sunday blasted a "Friends of Syria" meeting in Istanbul that is seeking ways to up the pressure on President Bashar Assad's regime as a "platform for the enemies of Syria."

"Only the naive and those who want to see through the eyes of the Americans believe that this is a conference for the friends of the Syrian people," said Al-Baath newspaper, mouthpiece of Assad's ruling party of the same name.