Speaking in an interview with Al Arabiya on Tuesday, Mikhail Ulyanov said parties to the Vienna talks must focus on the issue of lifting US sanctions.
Saying that US sanctions against Iran remain an obstacle to negotiations, he added that no one says negotiations on Iran will be easy.
"I was surprised that the Western parties have expressed doubts about the seriousness of Iran in the negotiations", the senior Russian negotiator also noted.
The new round of sanctions removal talks between the representatives of Iran and the P4+1 group of countries -- Britain, France, Germany, Russia, and China -- was kicked off on Tuesday evening at the Coburg Hotel in Vienna.
The talks are focused on the removal of all sanctions imposed on Tehran after Washington's unilateral withdrawal from the agreement. The US is not allowed to directly attend the talks due to its pullout in 2018 from the landmark deal with Iran.
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