European leaders taking part in nuclear negotiations with Iran last weekend in Turkey described the talks as constructive. Tehran said a mutual understanding was reached during negotiations but offered few specifics.
Iran is suspected of pursuing the technology needed to produce a nuclear weapon, an allegation the Iranian government denies. The International Atomic Energy Agency has said there may be some military aspects to certain parts of Iran's nuclear program.
Another round of talks is expected in Baghdad, although a date hasn't been announced.
Iranian Foreign Minister Ali Akbar Salehi described the Istanbul talks as a good "starting point."
"We are optimistic about the outcomes of the negotiations and their continuation in Baghdad in line with resolving the nuclear issue while asserting Iran's absolute and legitimate rights," he was quoted by Iran's state-funded broadcast Press TV as saying.
Salehi said Iran would continue work on its nuclear energy program despite pressure from governments wary of its ambitions.