President Donald Trump held off of terminating a nuclear agreement with Iran on Friday but said he would if fatal flaws are not fixed.

Britain led criticism of Donald Trump after the US President said he would no longer certify an international nuclear deal with Iran.

Theresa May issued a joint statement with German Chancellor Angela Merkel and French President Emmanuel Macron saying they ‘stand committed’ to the agreement.

'Iran is not living up to the spirit of the deal, 'Trump said, skewering the country's government as a 'menace' for its pursuit of ballistic missiles and its support for terror initiatives. Tehran may also be in cahoots with North Korea, he said.

Trump faced a Sunday deadline dictated by Congress for the administration to say that Iran is in compliance with the nuclear pact. 'I am announcing today that we cannot and will not make this certification,' Trump said in a Diplomatic Room speech on Friday.

'We will not continue down a path whose predictable conclusion is more violence, more terror, and the very real threat of Iran’s nuclear breakout,' Trump stated.

He did not demand Congress re-impose nuclear sanctions that would effectively end the United State's participation in the multi-nation agreement spearheaded by Barack Obama's administration yet warned that he could use his authority to cancel the deal at any time.

Trump said his administration would be slapping Iran's Revolutionary Guard with tough new punishing actions for terror financing, though. That activity is not regulated by the existing agreement.

President Donald Trump held off of terminating a nuclear agreement with Iran on Friday but said he would if fatal flaws are not fixed

The administration is pursing a new strategy toward Iran that takes into account its ballistic missile program, animosity toward Israel, it's support for Lebanon's Hezbollah movement, its affiliation with Palestine's Hamas and its backing of other terror groups.

Relaying the history of the United States' fraught relationship with Tehran since a 1979 revolution, Trump declared Iran 'under the control of a fanatical regime' that has harbored terrorists and bombed the American military and U.S. embassies.

'The Iranian dictatorship's aggression continues to this day,' Trump said Friday.

Iran continues to develop and deploy missiles, threaten the U.S. and its allies and harass American ships, Trump proclaimed in his White House address. It has also targeted its own citizens, he said, and instigated sectarian violence in Iraq.

In light of those actions, Trump said the U.S. 'should not take lightly its sinister vision for the future.'

'The regime’s two favorite chants are “Death to America” and “Death to Israel," he said.

Trump made the case his Friday speech that Iran's its non-nuclear behavior violates the spirit of the regional stability it was intended to encourage.

'As I have said many times, the Iran deal was one of the worst and most one-sided transactions the United States has ever entered into,' he argued. 'We need negotiators who will much more strongly represent America's interest.'

He berated the previous administration for giving Iran a 'political and economic lifeline' and a 'massive cash settlement' that the U.S. forked over at the beginning, and not the end, of the agreement.

'A large portion of which was physically loaded onto an airplane and flown into Iran,' Trump said, rehashing a $1.7 billion payment the U.S. made to Tehran at the beginning of last year. 'Just imagine the sight of those huge piles of money being hauled off by the Iranians waiting at the airport for the cash. I wonder where all that money went.'

Revisiting the issue outside the White House on Friday afternoon as he prepared for a short trip, Trump said Iran owed Obama a 'thank you.'

'We're very unhappy with Iran. They have not treated us with the kind of respect that they should be treating. They should have thanked Barack Obama for making that deal,' Trump said.

'They were gone. They were economically gone. He infused $100 to $150 billion into their economy. He gave them $1.7 billion in cash. And they should be, "Thank you, President Obama." They didn’t say that.'

The Republican president said more than once as as candidate that he would rip up the Iran deal because it's unfair to the U.S. He told reporters Friday afternoon, 'I may do that.'

'The deal is terrible. So what we've done is, through the certification process, we'll have Congress take a look at it, and I may very well do that. But I like a two-step process much better,' he asserted.

Under U.S. law, Trump was required to notify Congress by Sunday whether Iran was complying with the accord that was negotiated over 18 months by the Obama administration and determine if it remains a national security priority.

His said that it isn't, bringing up multiple violations, and asked lawmakers to codify tough new requirements for Tehran to continue to benefit from the sanctions relief that it won in exchange for curbing its atomic program.

He also announced a long-anticipated measure to impose sanctions on portions of Iran's Revolutionary Guard Corps by designating them terrorist organization under an existing executive order.

'The reckless behavior of the Iranian regime, and the IRGC in particular, poses one of the most dangerous threats to the interests of the United States and to regional stability,' the White House said in a statement released ahead of the speech.

Trump said the IRGC is the 'corrupt, personal terror force and militia' of Iran's supreme leader, Ali Khamenei.

A White House statement released ahead of Trump's remarks denounced the Obama administration for its 'myopic focus on Iran's nuclear program to the exclusion of the regime's many other malign activities' and said the same 'mistakes' would not be repeated.

'The Trump administration's Iran policy will address the totality of these threats from and malign activities by the Government of Iran and will seek to bring about a change in the Iranian's regime's behavior,' it said.

Trump faced a Sunday deadline dictated by Congress for the administration to say that Iran is in compliance with the nuclear pact. 'I am announcing today that we cannot and will not make this certification,' Trump said in a Diplomatic Room speech on Friday

Trump's administration will now pursue carefully concocted plan to strengthen the deal.

U.S. officials said Thursday that Trump would like a companion agreement that addresses Iran's illicit ballistic missile tests and terror financing, two issues that are separate yet related to his belief that Iran is violating the spirit of the existing accord.

Additionally, Trump wants a major amendment to the legislation that gave Congress oversight over nuclear sanctions.

The administration would prefer that Congress legislate 'trigger points' that will set off automatic sanctions if they are violated.

Trump had been hinting that he would take steps to either renegotiate a deal - something that Tehran says is off the table - or scrap it entirely for weeks in anticipation of the Oct. 15 deadline to report to Congress. It was the administration's push for amended oversight legislation that was kept tightly under wraps.

In a briefing at the White House yesterday evening, Secretary of State Rex Tillerson said Congress inserted itself into the equation because the Obama administration refused to give it a say so in the first place.

'The Congress' reaction was, you didn't give us a chance, so we're gonna put oversight on you,' he said, offering an explanation for the current administration's desperate plea to the legislative branch for changes to Iran review legislation.

Trump chose not to take unilateral action up front in a strategic attempt to avoid the same fate, Tillerson indicated.

Activists participate in a protest in front of the White House October 12, 2017 in Washington, DC. Activists held a rally to "denouncing President Trump's anticipated decision to decertify the Iran nuclear deal

The administration is asking Congress to amend or replace legislation that currently requires him to certify Iranian compliance every 90 days.

Officials have said that Trump hates the requirement more than the nuclear deal itself because it forces him to take a position every three months on what he has repeatedly denounced as the worst deal in American history.

That frequency has also irritated aides who have complained that they are spending inordinate amounts of time on certification at the expense of other issues.

Tillerson told reporters that Senate Foreign Relations Chairman Bob Corker, with whom the president has been feuding partly because of Iran, more or less agreed that lawmakers demanded oversight of the deal as a rebuke to Obama.

It's far from certain that they will give up the authority now, he acknowledged, but the administration believes it is not entirely out of the question.

'I don't want to suggest to you that this is a slam dunk up there on the Hill. We know it's not. People have very strong feelings about this nuclear arrangement with Iran,' Tillerson said. 'But we also feel strongly. One of the weaknesses is that Congress never really got to express a view other than through this [legislation[ after the thing was already done. This is their opportunity to express that view.'

Tillerson declined to detail the lobbying that he and National Security Advisor HR McMaster have been doing on Capitol Hill and specified just two of the 'trigger points' they want to see in amended legislation - sanctions that will kick in if Iran tests ballistic missile and if they reach any of the deals built-in sunsets.

Other critical violations will be developed with input from lawmakers, he said.

'We've been socializing this on the Hill now for several weeks, quietly, so it's not to put anyone in a box or force them to take a position early on because it is a bit of a complicated issue and it does require one to think about, OK what's the benefit of doing this,' Tillerson stated.

'But so far in all of our discussions we've had on the Hill, certainly with leadership in the Senate, leadership in the House, they've been supportive, and in discussions we've had with the minority [on] both sides of the Hill as well, there's been interest in wanting to understand it.'

Secretary of State Rex Tillerson said the administration is fully aware that Congress could pursue an entirely different course of action, such as 'snap back' sanctions, and it's a risk the president is willing to run

Democratic Congressman Elliot Engel, the ranking member of the House Foreign Affairs Committee, said Thursday that he confused by the administration's plans.

'This talk of decertifying the agreement, then kicking it to Congress for some sort of magical fix just doesn’t make sense,' Engel stated. 'I wish I had more clarity on what the White House plans to do, but the White House apparently feels that Democratic members don’t need any kind of briefings. I’m frankly irked that many of us are being kept in the dark.'

Ben Cardin, the top Democrat on the Senate Foreign Affairs Committee, raked Trump over the coals after his speech for waiting so long after he took office to engage Congress on the issue.

'The Administration should have been working with Congress since January to develop and implement a comprehensive Iran policy. A serious policy would keep the JCPOA in place, demand rigorous enforcement of the agreement, and take steps to push back on Iran’s troubling, non-nuclear aggression,' Cardin said in a statement.

After Trump's announcement, Democrats piled on with complaints that Trump was putting national security at risk with decertification.

'For our own national security, I urge my colleagues to vote against reimposing sanctions as long as Iran is upholding its side of the agreement. If Congress reimposes sanctions, it’s the United States, not Iran that will have broken its commitments, further damaging our credibility on the international stage, making a diplomatic solution with North Korea that much harder,' said Sen. Dianne Feinstein.

Sen. John McCain, a Republican who voted against the Iran agreement when it came before Congess, said the changes Trump outlined are 'long overdue' and are a necessary check on a regime that 'has literally been getting away with murder.'

The only no vote against congressional review legislation, Republican Sen. Tom Cotton, said, 'The current deal paves the way to a nuclear weapon for Iran, so Congress and the President must seize this opportunity to fix the deal’s grievous flaws.

'The Iran deal disfigured our wider policy toward Iran, because President Obama was so scared that Iran would scuttle the deal that he pulled his punches on other issues,' Cotton said. 'By not certifying it, President Trump has given Iran a wake-up call and redirected our Iran policy toward advancing U.S. interests and those of our allies.'

The Iran Nuclear Agreement Review Act (INARA) of 2015 gives Congress 60 days to decide whether to take action if the administration takes steps to unravel the Iran nuclear agreement. With his announcement today, Trump kickstarted the review period in Congress.

It will be up to legislators to decide what to do next. The administration wants Congress follow its suggested route and amend INARA, although it knows that's not the most plausible outcome of the discussion.

'I don't want to suggest to you that we get a high chance of success, but there is an openness to talk about it, so that's, where do we start,' Tillerson said during a Thursday evening briefing with reporters at the White House.

Should Congress decide to reinstate sanctions on Iran, the United States will be in breach of the multi-nation nuclear agreement.

Trump's secretary of state said the administration is fully aware that Congress pursue that course of action.

'We may be unsuccessful. We may not be able to fix it,' Tillerson said. 'If we're not, then we may end up out of a deal.'

An Iranian woman walks past pictures of Iranian supreme leader Ayatollah Ali Khamenei (top L) and of late Iranian supreme leader Ayatollah Ruhollah Khomeini (top R). Trump's speech from the White House will address an array of Iran's troubling non-nuclear activities, officials have said

American allies have pressed the White House to remain in the nuclear accord.

Britain's Theresa May begged Trump in a phone call Tuesday not to exit the P5+1, as the participating countries are known. May said the UK has a 'strong commitment to the deal alongside our European partners.'

Foreign secretary Boris Johnson made a similar plea to his U.S. counterpart. 'The nuclear deal was an historic achievement,' he told Tillerson.

'It was the culmination of 13 years of painstaking diplomacy and has increased security, both in the region and in the UK,' Johnson said.

Trump said Friday that he had spoken to Britain's May and France's Emmanuel Macron.

'They would love me to stay in, only for one reason: Look at the kind of money that's being sent. You know, Iran is spending money in various countries,' Trump assessed. 'And I've always said it, and I say to them: Don't do anything. Don't worry about it. Take all the money you can get. They're all friends of mine.'

Trump said he told Macron to 'take their money; enjoy yourselves.'

'But we'll see what happens,' he said. 'Iran has to behave much differently.'

The Europeans, along with the other parties, Iran, Russia and China, have ruled out reopening the deal. But some, notably France, have signaled a willingness to tackle unresolved issues in supplementary negotiations.

Trump is seeking to engage with foreign leaders, particularly those that are also a part of of the JCPOA, Tillerson said.

'I think what he's saying is look, we'll try. We'll try. We'll go try and fix it. I think you're going to hear that he's not particularly optimistic, but I think rather than just walk he's saying alright i'm willing to give it a try and address these issues.'

Among the issues Europe is willing to look at expiration of several restrictions on advanced nuclear activity under so-called 'sunset clauses' that will allow Iran to begin ramping up its enrichment capabilities after 10 years, the end of an arms embargo and the eventual easing of demands for a halt to its missile program.

In anticipation of Trump's announcement, Republican legislators have drawn up a new version of the law replacing the current 90-day timetable with 'semi-annual' certifications, according to drafts seen by the Associated Press this week.

Corker said in a statement on Friday that his panel had agreed to fresh certification criteria to include items that are also the province of the U.N. nuclear watchdog and require the U.S. intelligence community to determine if Iran is carrying out illicit activity in facilities to which the International Atomic Energy Agency has not had access.

The certification would also demand that the intelligence community produce judgments on Iranian behavior not covered by the nuclear deal, including missile testing and development, backing for Hezbollah and Assad and threats to Israel and the Mideast more broadly, according to the drafts.