Oman FM in Iran as nuclear talks continue in Vienna
Iranian Foreign Minister Hossein Amirabdollahian welcomed Sayyid Badr Albusaidi upon his arrival, with the visit scheduled to focus on bilateral and international affairs, the IRNA news agency said.
Speaking at a joint briefing with his Omani counterpart, Amirabdollahian said there are still a few "extremely important issues in the negotiations in Vienna".
Oman has often acted as a go-between to help facilitate back-door diplomacy between the US and Iran, sometimes involving the release of prisoners.
Talks in Vienna aim to restore a 2015 nuclear deal that saw Tehran drastically limit its enrichment of uranium in exchange for the lifting of economic sanctions.
The diplomatic visit raised speculation that Oman may get involved as an intermediary in the ongoing nuclear talks, or deliver a US message to Iran.
Amirabdollahian also said in the briefing on Wednesday that Iran will "in no way" cross its "red lines" during the Vienna talks.
The US has participated indirectly in the ongoing talks because it withdrew from the accord in 2018 under then-President Donald Trump.
Trump later re-imposed crushing sanctions on Iran. President Joe Biden has signalled that he wants to rejoin the deal.