The White House publicly pressured Iran on Wednesday to revive the 2015 Iran nuclear agreement quickly, saying only a few weeks remain to restore the deal.

"Our talks with Iran have reached an urgent point," White House spokeswoman Jen Psaki told reporters, noting that the US special envoy for Iran, Rob Malley, has returned to Vienna for indirect talks with Iran on both sides resuming compliance with the pact.

"A deal that addresses the core concerns of all sides is in sight, but if it's not reached in the coming weeks Iran's ongoing nuclear advances will make it impossible for us to return to the JCPOA," she said, referring to the deal by the acronym for its official name, the Joint Comprehensive Plan of Action.

Psaki's comments echoed those of a senior U.S. State Department official who told reporters on Jan. 31 that "we only have a handful of weeks left" to revive the agreement.

Under the accord, Iran restricted its nuclear program to make it harder to obtain the fissile material to make a bomb. In return, the United States and other nations eased sanctions that have crippled Iran's economy.

Former US President Donald Trump abandoned the deal in 2018, arguing that it had failed to stop Iran's support for regional proxies and gave Tehran too much sanctions relief for the nuclear restrictions. He then restored U.S. sanctions, prompting Iran to begin violating the deal's nuclear limits a year later.

Reporting by Reuters