U.S. President Barack Obama urged Congress on Thursday not to add new sanctions against Iran as world powers attempt to negotiate a deal on Iran's controversial nuclear program,
But Obama warned that Washington is not changing its bottom line despite the potential for a nuclear deal with Tehran.
"Iran cannot have nuclear weapons and I'm leaving all options on the table to make sure that we meet that goal."
President Obama's comment at a news conference Thursday in Washington follows a surge in optimism among top U.S. diplomats that a deal with Iran is within reach.
But that optimism has alarmed U.S. lawmakers, many of whom say Iran cannot be trusted and that new sanctions are needed.
Obama says hitting Iran with new sanctions could scuttle a deal and that they are not necessary.
"We would leave in place the core sanctions that are most effective and have the most impact on the Iranian economy, specifically oil sanctions and sanctions in respect to banks and financing."
Iran insists its nuclear program is for peaceful purposes but the U.S. and others have accused Iran of seeking nuclear weapons.
The president said the proposed short-term deal would call for Tehran to stop advancing its nuclear program and subject Iran to more rigorous inspections in exchange for minimal sanctions relief. He said sanctions could then be ramped up again if Iran failed to comply.
Separately Thursday, the United Nations' nuclear agency said Iran has frozen expansion of its uranium enrichment capacity since August, when President Hassan Rouhani took office.
But Reuters reported Israeli Prime Minister Benjamin Netanyahu said Thursday he was "not impressed" by the IAEA report, saying Iran already has all the capacity it needs.
Israel has repeated warned against any deal with Tehran that does not completely eliminate Iran's ability to enrich uranium and produce a nuclear weapon.