The US will not lift its blockade on Iranian ports until a deal has been reached with Tehran, US President Donald Trump has said, amid continuing uncertainty over whether fresh talks to end the war will take place.

The blockade, which began a week ago, is absolutely destroying Iran, Trump wrote on his social media platform Truth Social, adding his country was winning the conflict by a lot.

His comments come with the temporary US-Iran ceasefire set to end on Wednesday, but with no certainty over whether a second round of peace talks will go ahead in Pakistan.

There is tightened security in Pakistan's capital in anticipation of a meeting. But US Vice President JD Vance - set to lead the US delegation - has not yet left Washington, while Iran says it has not decided whether to attend.

Since the blockade began, US forces have directed 27 vessels to turn around or return to an Iranian port, according to US Central Command (Centcom). The US also intercepted an Iranian-flagged cargo ship that attempted to breach the blockade, deeming it a violation of the ceasefire.

The situation remains fluid as both sides prepare for potential talks, with Iranian officials indicating they may refuse to attend unless the blockade is lifted.