Wang said such acts were the root cause of the Iranian nuclear issue, Reuters reported.
In 2018, then-president Donald Trump withdrew the United States from the world powers’ 2015 accord with Iran – known as the JCPOA – and reimposed harsh sanctions on Tehran.
The landmark agreement has been hanging by a thread since the US withdrawal which prompted Tehran a year later to step up its nuclear activities beyond the terms of deal in retaliation for the pullout.
The remaining signatories to the deal – Iran, Britain, China, France, Germany and Russia have been meeting in Vienna since early April to revive the accord and bring the US back to the JCPOA.
“To return to the deal, lifting sanctions on Iran first is the natural thing to do,” Wang said.
As the talks were in a “final sprint,” parties to the accord must redouble diplomatic efforts to “bring the JCPOA back on track,” Wang said.
Negotiators are expected to resume their talks in two downtown Vienna hotels on Saturday, according to diplomats, AFP reported.
Negotiators from the US are also taking part indirectly in the EU-chaired discussions.
Diplomats are hoping to conclude the negotiations before Iran’s presidential election on June 18.