The Turkish Foreign Ministry spokesman has welcomed Iran and the P5+1 leaving the door open for further negotiations after the Instanbul talks failed to yield results.

Iran and the P5+1 -- the five permanent members of the UN Security Council plus Germany -- wrapped up their second round of comprehensive talks in the Turkish city of Istanbul on Saturday.

The Iranian delegation was headed by Secretary of Iran's Supreme National Security Council Saeed Jalili and European Union's foreign policy chief Catherine Ashton also chaired representatives from the US, UK, France, Russia, China and Germany.

"We are glad that both sides have left the door open for future negotiations," Selcuk Unal said at a press conference after the conclusion of the two-day talks.

“We have been defending that this issue should be resolved by diplomatic means only since the beginning,” Xinhua quoted Unal as saying.

"The Istanbul meeting is just a culmination of this attitude," he added.

In a press conference following the talks, Jalili said Tehran is “still prepared for further negotiations with the P5+1, based on common issues… like we said in Geneva.”

“[Nuclear] fuel swap can be the basis for cooperation between nations… and it could be a subject for further negotiations,” he added.

The US and its allies accuse Iran of developing a military nuclear program, and used this pretext to pressure the UN Security Council to impose a fourth round of sanctions against Iran's financial and military sectors in June.

Iranian officials have repeatedly refuted the charges, arguing that as a signatory to the Nuclear Non-Proliferation Treaty and a member of the International Atomic Energy Agency, Tehran has a right to use peaceful nuclear technology.