The US military says it will commence a blockade of Iranian ports from 10:00 ET (14:00 GMT) on Monday
The US “will not impede” vessels transiting the Strait of Hormuz to or from other countries – oil prices climb above $100 again over the tensions
It follows a Truth Social post from President Donald Trump saying the US Navy will “blockade any and all ships” trying to enter or leave the strait
Iran says any military vessels that approach the shipping route will be “dealt with severely”, while the country’s parliament speaker says Tehran will not “surrender under threats”
Trump also says “I don’t care” if Iran returns to negotiations or not, adding that peace talks in Islamabad, Pakistan failed because Tehran won’t “give up its nuclear ambitions”
Iran says the two sides were “inches away” from a deal in Pakistan, but Tehran was then met with “maximalism” and “shifting goalposts”
Trump’s posts pose a number of new challenges for the US, writes our North America correspondent
