Iran's atomic chief warned on Tuesday that Tehran may resume uranium enrichment at high levels within five days if the United States abandoned the 2015 nuclear deal signed with western powers.
"If we decide, we can reach 20 percent (uranium) enrichment within five days in Fordow (underground nuclear plant)," said Ali Akbar Salehi, head of Atomic Energy Organization of Iran.
“Of course we do not favor this option and we are exerting great effort to implement the nuclear agreement,” he added.
However, Salehi who was reappointed this month as vice president and the head of the Atomic Energy Organization, said his main priority would be to protect the deal, known by its acronym JCPOA.
US President Donald Trump had during his presidential campaign repeatedly threatened to eliminate the nuclear agreement. After his elections, he imposed new sanctions on Tehran over its nuclear program.
Washington and Tehran have since accused each other of violating the spirit of JCPOA.
The deal that Iranian President Hassan Rouhani championed with the United States, Russia, China and three European powers led to the lifting of most sanctions against Tehran in return for curbs on its nuclear program.
Rouhani has intensified efforts to protect the deal against Washington's return to an aggressive Iran policy, after Trump approved the new sanctions.
Rouhani warned last week that Iran could abandon the nuclear agreement "within hours" if the United States imposes any more new sanctions.
The US Treasury imposed sanctions on six Iranian firms in late July for their role in the development of a ballistic missile program after Tehran launched a rocket capable of putting a satellite into orbit.
Trump also signed in August a US Senate bill that imposed sanctions on Iran, Russia and North Korea.