WASHINGTON — A flurry of diplomatic contacts and reports of major progress suggest that indirect talks between the U.S. and Iran may be nearing an agreement. That’s despite efforts by U.S. officials to play down chances of an imminent deal that would bring Washington and Tehran back into compliance with the 2015 nuclear deal.

With the negotiations in Vienna on hiatus, the U.S. and Britain denied Iranian reports that any agreement was at hand with Iran for a swap of American and British prisoners. Such an exchange could be a confidence-building measure to revive the nuclear deal.

A U.S. return to the deal would be the biggest and most controversial foreign policy initiative in the early months of Joe Biden’s presidency. It would revive a deal that top Biden aides put together during their years in the Obama administration, only to see President Donald Trump pull out and try to prevent the U.S. from ever returning. Rejoining it — and making the concessions required to do so — would enrage Republicans and likely unsettle Israel and Gulf Arab allies.

Even as Secretary of State Antony Blinken and British Foreign Secretary Dominic Raab rejected the prisoner swap reports at a news conference Monday in London, senior American diplomats were in the Middle East meeting Gulf Arab leaders. And two of the nuclear deal’s biggest proponents in Congress — Democratic Sens. Chris Coons and Chris Murphy — were touring the region.

Those discussions follow a week of top-level meetings in Washington between Biden; his national security adviser, Jake Sullivan; Blinken; his deputy, Wendy Sherman; special Iran envoy Rob Malley; and others with the head of Israel’s spy agency and Israeli Prime Minister Benjamin Netanyahu’s top national security aide.

The Israelis are adamantly opposed to any U.S. rapprochement with Iran, which they regard as an existential threat to the Jewish state. At least three separate meetings were held with the Israelis last week, including one Friday with Mossad chief Yossi Cohen at which Biden made an appearance. White House press secretary Jen Psaki said Cohen was briefed on the Vienna discussions “and the progress being made there.”

Later Friday, and on Saturday, reports emerged from Iran and Iran-linked media outlets that an agreement had been struck on what the U.S. would provide in return for Iran returning to compliance with the 2015 deal, which had given billions of dollars in sanctions relief in exchange for curbs on its nuclear program. On Sunday reports of the prisoner swap deal emerged.

U.S. officials were quick to bat those reports down as premature and inaccurate, although the broad contours of potential sanctions relief are well-known and Washington has made no secret of its eagerness to free Americans held in Iran.