President Donald Trump on Tuesday said he was extending a ceasefire with Iran to give more time for negotiations, but would maintain a US naval blockade of the country's ports.

Trump posted on social media that he would "extend the Ceasefire" until Iran came up with a proposal to end the conflict. However, he "directed our Military to continue the Blockade."

Trump's ceasefire extension came hours before it was believed to be set to expire.

It also came as the White House said Vice President JD Vance would not be going to Pakistan for what had been expected to be a second round of peace talks.

The US president cast the breakdown in more talks as resulting from Iranian infighting, adding that Pakistan's leaders had asked him to extend the truce.

"Based on the fact that the Government of Iran is seriously fractured, not unexpectedly so and, upon the request of Field Marshal Asim Munir, and Prime Minister Shehbaz Sharif, of Pakistan, we have been asked to hold our Attack on the Country of Iran until such time as their leaders and representatives can come up with a unified proposal," Trump posted on his Truth Social site.

But the blockade of ports on Iran's coast in the Strait of Hormuz will remain in place, Trump said, while the US military will "in all other respects, remain ready and able."

The ceasefire, he said, will be extended "until such time as their proposal is submitted, and discussions are concluded, one way or the other."