Iran's president Rouhani says the nation has acted rationally, logically and tactfully during nuclear negotiations, according to the ISNA news agency.
But he added: "We have said to the negotiating sides that we will not answer to any threat, sanction, humiliation or discrimination.
"For us there are red lines that cannot be crossed. National interests are our red lines that include our rights under the framework of international regulations and (uranium) enrichment in Iran", he added.
Mr Rouhani also said that economic sanctions were harmful to the countries imposing them, not just Iran.
On Saturday, Iran and six world powers failed in talks to agree a deal to curb Tehran's nuclear programme but said differences had narrowed and they would resume negotiations in 10 days.