US President Donald Trump has instructed negotiators to proceed cautiously in talks with Iran, warning against rushing into a deal.

The comments come as Washington and Tehran continue to observe a ceasefire, but Iran has imposed controls on Gulf shipping and the US has blockaded its ports.

A deal to end the Middle East war could be reached as early as today, but Iran has insisted that any agreement would not limit its nuclear programme.

The blockade of the Strait of Hormuz, a crucial waterway for global oil exports, remains in place.