Iran's president has vowed it will abide by the terms of the preliminary nuclear agreement it signed with six world powers, so long as they do too.
"The world must know that we do not intend to cheat," Hassan Rouhani said in a televised address to the nation.
But Mr Rouhani warned that Iran would have other options if world powers "one day decide to follow a different path".
The framework deal signed on Thursday will see Iran curb nuclear activities in return for relief from sanctions.
Earlier Israeli Prime Minister Benjamin Netanyahu warned that it posed a grave danger to the region, in particular his own country.
He said any compressive accord, due before 30 June, had to include a "clear and unambiguous Iranian recognition of Israel's right to exist".
But the White House said the US would not sign an agreement over Iran's nuclear programme that would threaten Israel.
White House spokesman Eric Shultz also announced that President Barack Obama would on Friday discuss the framework agreement with Congressional leaders, some of whom have been very sceptical of a deal.
President Rouhani reiterated that Iran's nuclear programme was peaceful.
The country was "not two-faced", he said, and would honour any final deal provided the P5+1 - the US, UK, France, Russia, China and Germany - did the same.
"If the other side acts on its promises, Iran will abide by its promises. If, however, they one day decide to follow a different path, our nation too will be always free to make [another] choice."
Mr Rouhani also stressed that the world now accepted Iran had the right to enrich uranium on its own soil, and that enrichment was not a threat to anyone.
There's been celebration through the night across Iran and a hero's welcome for Foreign Minister Javad Zarif. But the deal he's brought home has been dismissed by hardliners who say Iran surrendered too much in exchange for too little.
John Kerry also faces a mix of support and scepticism in the US Congress. The loudest condemnation has come from Israel's Prime Minister Netanyahu, who insists this deal doesn't block but helps Iran build a nuclear bomb.
As hard as it was to reach this preliminary agreement, it will be even harder to draft a final deal by the end of June. But, if negotiators do it, it will be a victory for diplomacy which, they believe will make the world a much safer place.