In May, a year after Trump's withdrawal, President Hassan Rouhani said that Iran would roll back its commitments under the deal in stages every 60 days in an effort to force the other parties to deliver on their side of the bargain.
Based on the 2015 nuclear deal between Iran and world powers, the Joint Comprehensive Plan of Action (JCPOA), the Islamic Republic of Iran undertook to keep its uranium enrichment below 3.67 percent for 15 years from 17 January 2016 to 16 January 2031.
Pence's tough stance was echoed by U.S. Secretary of State Mike Pompeo and National Security Adviser John Bolton, both Iran hawks, who spoke later on the same event. Mr. Kamalvandi also suggested using new or more centrifuges, which are limited by the deal.
Trump has even introduced full ban on Iran's oil export, a move which has been described as an economic war against Tehran.
President Donald Trump, who withdrew the United States from the deal and reimposed sanctions, is now pressuring Tehran to renegotiate the pact, saying "Iran had better be careful".
"We have no hope nor trust in anyone nor any country but the door of diplomacy is open", Mousavi said.
A spokesman for the Atomic Energy Organisation of Iran said the 20% enrichment is the third phase in scaling down its commitments under the 2015 deal.
Iran denies it seeks nuclear weapons, but the nuclear deal sought to prevent that as a possibility by limiting enrichment and Iran's stockpile of uranium.
"Iran has threatened recently to destroy Israel", Netanyahu said in a video clip posted on Tuesday. He didn't elaborate on what actions the USA might consider, but he told reporters: "Iran's doing a lot of bad things".
The United States, China and Russian Federation also signed the 2015 Iran nuclear deal.
Vice President Mike Pence, who spoke to the same group, added a warning: 'Iran should not confuse American restraint with a lack of American resolve, ' reiterating Washington's resolve to protect US personnel and citizens in the Middle East. They have little appetite to sign on to new sanctions, although they have even less interest in a nuclear Iran.
The top diplomats called on Iran to comply with the JCPOA.
As part of its campaign, the USA has re-imposed sanctions on exports of Iranian crude oil, which have tanked the Iranian economy.
Netanyahu has been a vocal critic of the nuclear deal struck by world powers and Iran in 2015, and has called on Europe to impose fresh sanctions in response to Iran's breach of it. The downing of the drone almost led to a United States military strike against Iran; it was called off at the last minute by Trump.
Earlier in the week, Iranian Foreign Minister Mohammad Javad Zarif confirmed that the country had surpassed the 300-kilogram (660-pound) low-enriched uranium stockpile limit, agreed on under the JCPOA.
The latest moves come amid mounting military tensions between the U.S. and Iran that nudged close to outright hostility before Donald Trump last month cancelled airstrikes drawn up in response to the shooting down of a U.S. drone. The remaining signatories to the deal include Britain, France, Germany, China and Russian Federation.
Iran says if the European Union fails to find a way to keep the nuclear deal viable within two months, it will do something "somehow stunning". "In exchange, the deal gave away billions of dollars in cash sanctions really Iran has used the phone more terrorist attacks on innocence across the region", Pence said.