Iran President Hassan Rouhani committed to reaching an agreement at nuclear discussions in Austria - assuming the U.S. acts with "honesty."

Diplomats from across the European Union, Iran, the U.K., Russia and China met this week in Vienna to go over material produced by two expert working groups on the topic of the Iranian nuclear program.

"After days of intensive talks, it appears we are now on the right track," Iranian negotiator Abbas Araghchi tweeted. "But (there is) a difficult way to go."

American President Joe Biden is looking to rejoin a 2015 nuclear deal between the countries from which the U.S. withdrew in 2018 under former President Donald Trump.

Under the previous Joint Comprehensive Plan of Action, Iran committed to eliminate its stockpile of medium-enriched uranium, drastically reduce its reserves of low-enriched uranium, as well as temporarily decrease the number of gas centrifuges in operation.

Trade and economic sanctions against Iran were greatly reduced in return, though this did not last. The U.S. and Israel soon found fault with the deal and accused the Rouhani administration of failing to disclose a past covert nuclear arms program.

Rejoining the deal was a key pillar of Biden's 2020 presidential campaign and this week, American diplomats held indirect talks with their Iranian counterparts that State Department representative Ned Price called "businesslike and positive."

"Progress has been made," EU diplomat Enrique Mora said.