White House national security spokesperson John Kirby said Thursday the negotiations on the 2015 nuclear deal with Iran "are pretty much complete at this point."

"There's a deal on the table. They ought to take it," he told reporters in Washington. "Time does appear to be getting very short in terms of being able to get to a deal."

Indirect talks between Tehran and Washington resumed in Vienna with a meeting between Iran's chief nuclear negotiator and the EU's Enrique Mora, who coordinates the talks aimed at salvaging the nuclear deal.

Little remains of the deal, which lifted sanctions against Tehran in exchange for restrictions on its nuclear program. But then-President Donald Trump ditched the deal in 2018 and reimposed harsh sanctions.

"You’ve heard the president say we’re not going to wait forever for Iran to take this deal," Kirby said.

"I’m not going to slap a label on it and say ‘last ditch,’ but ... we urge Iran to take this deal on the table," he said.

The proposed deal would see Iran agree to stringent controls on its nuclear sector, which it insists has only civilian purposes but is suspected of harboring a secret military program.

In return, Iran would see a gradual lifting of crippling economic sanctions.