Donald Trump has approved plans to attack Iran, but has not made a final decision on whether to strike the country, the BBC's US partner CBS reports, Associated Press reported.

The US president held off from initiating strikes in case Iran agreed to abandon its nuclear programme, a senior intelligence source told CBS. Trump is reportedly considering a US strike on Fordo, an underground uranium enrichment facility in Iran.

Iran's Supreme Leader Ayatollah Ali Khamenei on Wednesday rejected Trump's demand for unconditional surrender, as the US president said his patience had run out, according to Associated Press.

On Wednesday, Trump said, "I may do it, I may not do it", when asked a question about US involvement in Iran.