The Government in Iran has rejected a United Nations demand for it to suspend its uranium-enrichment programme, saying no international body can force it to do so.
The UN resolution also called on Iran to answer all outstanding questions about its nuclear programme by November.
The International Atomic Energy Agency is investigating allegations that the country is trying to develop nuclear weapons.
Meanwhile, a team of inspectors from the UN nuclear watchdog have arrived in the South Korean capital, Seoul, to resume an investigation into secret nuclear experiments there.
The inspectors will investigate South Korea's failure to declare three separate sites for the production of uranium metal, which was used as raw material for some of the experiments.
North Korea has said it will not return to talks on its own nuclear programme until South Korea's activities have been fully investigated.
