Supreme leader Ayatollah Ali Khamenei voiced his support on Sunday for Iran's talks with world powers over its disputed nuclear programme while expressing pessimism about them. "No one should see our negotiating team as compromisers," Khamenei, Iran's top decision-maker on its nuclear drive, was quoted as saying on his official website. "I am not optimistic about the (nuclear) negotiations but, with the grace of God, we will not suffer losses either," he added.