WASHINGTON/TORONTO (Reuters) - Western allies stepped up pressure on U.S. President Donald Trump on Monday to keep alive an international nuclear deal with Iran, with French President Emmanuel Macron due to urge him in person not to tear up the 2015 agreement.

Overview of the 2nd Preparatory session of the 2020 Non Proliferation Treaty (NPT) Review Conference at the United Nations in Geneva, Switzerland April 23, 2018. REUTERS/Denis Balibouse

Trump has said that unless European allies fix what he has called its “terrible flaws” by May 12, he will restore U.S. economic sanctions on Iran, which would be a severe blow to the pact.

Macron, who arrived in Washington on Monday for a state visit, said on Sunday there was no “Plan B” for keeping a lid on Iran’s nuclear ambitions.

Minutes after Macron’s plane touched down, the White House said it had no announcements on the Iran deal. White House spokeswoman Sarah Sanders added, “The president has been extremely clear that he thinks it’s a bad deal. That certainly has not changed.”

The agreement between Iran, the United States, China, Russia, Britain, France and Germany was born of longstanding concern among major powers that Iran was seeking to develop an atomic weapon and imposed curbs on Iran’s nuclear program in exchange for sanctions relief for Tehran. Critics of the pact, including Trump, have said it does not adequately contain Iran.

Trump sees three defects: a failure to address Iran’s ballistic missile program; the terms under which international inspectors can visit suspect Iranian nuclear sites; and “sunset” clauses under which limits on the Iranian nuclear program start to expire after 10 years.

German Foreign Minister Heiko Maas said both Macron and German Chancellor Angela Merkel, who is due to meet Trump in Washington on Friday, would urge the U.S. president to stay in the deal, which is formally called the Joint Comprehensive Plan of Action (JCPOA).

“We believe it is extremely important to uphold this agreement. Were it to fail or the U.S. to drop out, we would not have anything comparable to it and we fear that the situation would significantly deteriorate with everything that goes with it,” Maas told reporters.

He was speaking at a meeting in Toronto of foreign ministers from the Group of Seven leading industrialized nations.

Britain’s foreign minister, Boris Johnson, echoed this, telling reporters in Toronto, “There is a strong view around the (G7) table that we need to make the case for the JCPOA.”

“We accept that Iranian behavior has been disruptive in the region, we accept the president (Trump) has some valid points that need to be addressed, but we believe they are capable of being addressed (inside the deal),” Johnson said.

‘ENCOURAGE’ TRUMP TO STAY

Iran has said it will stick to the accord as long as the other parties respect it, but will “shred” it if Washington pulls out. Iranian Foreign Minister Mohammad Javad Zarif called on European leaders on Monday to support it.

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“It is either all or nothing. European leaders should encourage Trump not just to stay in the nuclear deal, but more important to begin implementing his part of the bargain in good faith,” Zarif wrote on Twitter.

On a visit to Beijing, Russian Foreign Minister Sergei Lavrov said he had agreed with his Chinese counterpart to block any U.S. attempt to sabotage the deal.

Trump’s opposition to the deal has been welcomed by Israel, which has rejected the pact since it was being hammered out under former U.S. President Barack Obama’s administration.

“Israel will not allow regimes that seek our annihilation to acquire nuclear weapons. This is why we opposed so resolutely the Iran deal, because it gives Iran a clear path to a nuclear arsenal,” Israeli Prime Minister Benjamin Netanyahu said in a speech to foreign diplomats on Monday in Jerusalem.

Listing objections, Netanyahu added, “This is why this deal has to be either fully fixed or fully nixed.”

At a nuclear non-proliferation conference in Geneva on Monday, there were repeated calls for parties to the deal to ensure its implementation and preservation.

U.N. High Representative for Disarmament Affairs Izumi Nakamitsu said it “continues to be the best way to ensure the exclusively peaceful nature of Iran’s nuclear program and to realize the promised tangible economic benefits for the Iranian people.”

Trump’s threat to restore U.S economic sanctions on oil-producing Iran have been one factor helping drive up global oil prices this month to their highest since late 2014.