Six world powers have begun a fresh round of talks with Iran about its controversial nuclear programme.The talks are being held in the Iraqi capital, Baghdad, at Iran's request.They come a day after the UN's nuclear watchdog held talks with Iran to try to gain better access to the regime's nuclear installations.Iran's Foreign Minister Ali Akbar Salehi says any efforts by Western powers to put pressure on Iran at the talks would be "futile".But he told a news conference in Tehran on Wednesday that there were reasons to be optimistic about the negotiations."The ideas fielded to us speak of the fact that the other side would like to make Baghdad a success. We hope that in a day or two we can bring good news."The five permanent members of the UN Security Council - the US, Britain, France, Russia and China - plus Germany are seeking to persuade Iranian officials to scale back their nuclear programme.