United States President Donald Trump has warned Iran it had “better be careful” after Tehran said on Sunday it planned to boost uranium enrichment beyond the limits set in the 2015 nuclear deal. Mr Trump did not specify what response he was considering, but told reporters in New Jersey that “Iran will never have a nuclear weapon”. “Iran better be careful, because you enrich for one reason and I won’t tell you what the reason is, but it’s no good. They better be careful,” Mr Trump said. The US Secretary of State Mike Pompeo said on Twitter on Sunday that Iran’s decision to raise its uranium enrichment to 5 per cent would lead to “further isolation and sanctions”. “Nations should restore the longstanding standard of no enrichment for Iran’s nuclear program. Iran’s regime with nuclear weapons would pose an even greater danger to the world,” he wrote.