U.S. President Donald Trump on Tuesday accused Iran of having repeatedly violated a temporary truce due to expire soon, with new peace talks mired in doubt after Tehran said it had not yet sent a delegation.

U.S. Vice President JD Vance, expected to lead a U.S. delegation at upcoming negotiations with Iran in Pakistan, was still in Washington midday Tuesday to participate in meetings, the White House said.

"Additional policy meetings are taking place at the White House in which the vice president will participate," an official said in a brief statement sent to AFP shortly after 1700 GMT.

There appeared to be movement toward another round of U.S.-Iran ceasefire talks Tuesday as two regional officials told The Associated Press that both countries have signaled a return to Pakistan for discussions. There was no immediate word on timing of talks.

Iran said it had yet to decide whether to attend a new round of peace negotiations with the United States, as Washington's delegation prepared to depart for Pakistan on Monday.

In the leadup and throughout the seven-week war, U.S. President Donald Trump has faced criticism from the left and from some of his own supporters that he followed Israel’s lead into launching the conflict.

Japan on Monday issued an advisory for northern coastal areas for an increased risk of a possible mega-quake induced by a major quake earlier in the day.

The Cabinet Office and the Japan Meteorological Agency said there is 1% chance for a mega-quake occurring on the northern Japanese coast in the next week or so following the powerful quake earlier Monday near the Chishima trough.

U.S. President Donald Trump said U.S. negotiators will be in Pakistan Monday to resume talks on ending the war with Iran, as he again threatened to destroy its power plants and bridges if no deal is reached.

In a social media post Sunday, Trump also accused Iran of violating the countries' two-week ceasefire with attacks Saturday in the Strait of Hormuz.

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.

Iran's top national security body said that the country was reviewing "new proposals" received from the United States, even as it warned that its negotiators would cut no compromises with Washington.

U.S. President Donald Trump on Saturday warned Iran not to "blackmail" Washington with its flip-flopping on the fate of the Strait of Hormuz, after Tehran declared the strategic waterway once again closed.

"We're talking to them. They wanted to close up the strait again -- you know, as they've been doing for years -- and they can't blackmail us," Trump said at a White House event.