President Donald Trump on Tuesday, pulled the United States out of an international agreement aimed at stopping Iran from obtaining a nuclear bomb, and said he would re-impose economic sanctions on Tehran immediately.

The decision is likely to raise the risk of conflict in the Middle East, upset America’s European allies and disrupt global oil supplies, reports Reuters.

US President Donald Trump signs a document reinstating sanctions against Iran after announcing the US withdrawal from the Iran Nuclear deal, in the Diplomatic Reception Room at the White House in Washington, DC, on May 8, 2018.

The 2015 deal, worked out by the United States, five other international powers and Iran, eased sanctions on Iran in exchange for Tehran limiting its nuclear programme.

Trump says the agreement, the signature foreign policy achievement of Trump’s predecessor Barack Obama, does not address Iran’s ballistic missile programme, its nuclear activities beyond 2025 or its role in conflicts in Yemen and Syria.

Trump said he was willing to negotiate a new deal with Iran, but Tehran has already ruled that out and threatened unspecified retaliation if Washington pulled out.

Iranian state television said on Tuesday that Trump’s decision to withdraw was “illegal, illegitimate and undermines international agreements.”

Renewing sanctions would make it much harder for Iran to sell its oil abroad or use the international banking system.

The Iran deal may remain partially intact, even without the United States. Iranian President Hassan Rouhani suggested on Monday that Iran could remain in the accord with the other signatories that stay committed to it.

Trump’s move is a snub to European allies such as France, Britain and Germany who are also part of the Iran deal and tried hard to convince the U.S. president to preserve it. The must now scramble to decide their own course of action with Tehran.