TEHRAN, April 19 -- The strategic Strait of Hormuz was again closed on Sunday in the stand-off between Iran and the United States, with Iran's powerful parliament speaker signalling a final peace deal remained "far" off despite some movement in negotiations.

As mediation efforts continued following high-level talks in Pakistan that failed to reach a deal, Iran said it will not allow the crucial maritime trade chokepoint to re-open until the United States ends a blockade of Iranian ports.

Mohammad Bagher Ghalibaf, speaker of the Iranian parliament, said in a televised address on Saturday night that there had been "progress" with Washington "but there are many gaps and some fundamental points remain".

"We are still far from the final dis...