Iran’s foreign minister said on Thursday that US demands to change its 2015 nuclear agreement with world powers were unacceptable. US President Donald Trump has warned that unless European allies rectify the “terrible flaws” in the international accord by May 12, he will refuse to extend US sanctions relief for the oil-producing country. “Iran will not renegotiate what was agreed years ago and has been implemented,” Foreign Minister Mohammad Javad Zarif said in a video message posted on YouTube. A senior adviser to Iranian Supreme Leader Ayatollah Ali Khamenei also warned Europeans on Thursday over “revising” the nuclear deal, Reuters reports. “Even if US allies, especially the Europeans, try to revise the deal… one of our options will be withdrawing from it,” state television quoted Ali Akbar Velayati as saying.