The Biden administration has restored a sanctions waiver to Iran, a senior State Department official said on Friday, as indirect talks between the United States and Iran on returning to the 2015 nuclear agreement entered the final stretch.

The waiver, which was rescinded by the Trump administration in May 2020, had allowed Russian, Chinese and European companies to carry out non-proliferation work at Iranian nuclear sites.

The waiver was needed to allow for technical discussions that were key to the talks about return to the deal formally known as the Joint Comprehensive Plan of Action (JCPOA), a State Department official said.

However, the official added that restoring the waiver was not a signal Washington was about to reach an understanding to return to the deal.

“Absent this sanctions waiver, detailed technical discussions with third parties regarding disposition of stockpiles and other activities of non-proliferation value cannot take place,” the official said.

The waiver covered the conversion of Iran’s Arak heavy water research reactor, the provision of enriched uranium for its Tehran Research Reactor and the transfer of spent and scrap reactor fuel abroad.

After then-U.S. President Donald Trump quit the nuclear deal in 2018 and reimposed harsh sanctions, Iran gradually started violating the pact’s nuclear curbs.

The United States and Iran have held eight rounds of indirect talks in Vienna since April aimed at reinstating the pact that lifted sanctions against Tehran in exchange for restrictions on its nuclear programme.

The latest talks in Vienna were “among the most intensive that we had to date” a U.S. official told reporters on Monday, adding that there has been some progress in narrowing down the list of differences and that now was the time for political decisions.