Iranian President Ebrahim Raisi said during a meeting with visiting Irish foreign and defence minister Simon Coveney that "the rights of the Iranian people must be respected" in the ongoing negotiations.

Raisi also hailed Ireland's "independence from the United States and some European countries", adding that the two countries have "vast capabilities" to strengthen ties, according to state news agency IRNA.

Iran is engaged in negotiations with Britain, China, France, Germany and Russia directly and with the United States indirectly to revive the deal formally called the Joint Comprehensive Plan of Action (JCPOA).

Also on Monday, Iranian Foreign Minister Hossein Amir-Abdollahian said that he believed an agreement is "at hand" soon, provided that the US and European parties "are serious" about returning to full compliance with the deal.

Speaking at a joint press conference with Coveney, the Iranian top diplomat said: "We are serious and ready to reach a good agreement."

The deal offered Tehran sanctions relief in exchange for curbs on its nuclear programme.

But the US unilaterally withdrew from the JCPOA in 2018 under then-president Donald Trump and reimposed stiff economic sanctions, prompting Tehran to begin rolling back on its commitments.

- 'Serious and committed' -

Irish foreign minister Coveney on Monday said he believed the Western parties to the deal to be "serious and committed".

"I do believe that the other parties to the JCPOA, in particular Western countries, are deeply committed to making this work," Coveney said told reporters, alongside his Iranian counterpart.

Ireland has been acting as the facilitator for UN Security Council Resolution 2231, which was agreed in 2015 to endorse the JCPOA.

"As facilitator, Ireland aims to assist in that process in whatever way we can, helping all parties to move this discussion forward," Coveney said.

"The restoration of the JCPOA in full would secure rapid and substantial sanction relief for Iran," he added.

Negotiations in Vienna aim to return the US to the deal, including through the lifting of sanctions on Iran, and to ensure Tehran's full compliance with its commitments under the pact.

"Our goal is the full removal of all JCPOA sanctions," Amir-Abdollahian said, adding that "it is better for the Islamic republic to reach an agreement today rather than tomorrow".

- 'Complicated and difficult' -

The Iranian top diplomat's remarks followed comments by his ministry's spokesman Saeed Khatibzadeh, who said earlier on Monday that talks were complicated but added that "there is no impasse in Vienna".

"The negotiations are complicated and difficult as they have reached key issues that need serious political decisions, especially by Washington," Khatibzadeh told a news conference.

"We need objective guarantees to make sure the US does not leave the agreement once again and that it honours its commitments," Khatibzadeh said.

"All JCPOA sanctions with any labels must be lifted at the same time," he added.

The drive to salvage the 2015 nuclear deal resumed in late November after a pause following Raisi's election in June.

Different parties to the agreement have in recent weeks signalled progress in the talks, with some saying the negotiations are in their final stage.