Iran on Friday vented frustration over fresh US sanctions which it says "violate" the terms of a 2015 landmark nuclear deal, raising its concerns at a meeting with major world powers in Vienna.

"We talked in detail about the sanctions and the instances that the Americans had delayed in fulfilling their commitments, the instances where they violated the deal," Tehran's lead nuclear negotiator Abbas Araqchi told reporters.

"We showed one by one the instances where the American side in the last year and a half acted without good will and even acted with ill intention." 

Araqchi said the United States was "trying to sabotage the situation, to threaten or scare off foreign companies to invest in Iran".

The regular quarterly meeting to review the deal heard, as Washington already confirmed earlier this week, that Iran is sticking to its side of the pact with the United States, Russia, China, Britain, France and Germany.

The parties said in a statement they welcomed "Iran's continued adherence to its nuclear-related commitments".

"All participants confirmed their continued adherence to (the) commitments and stressed the need to ensure its full and effective implementation in a constructive atmosphere," the statement read.

The gathering among senior diplomats was held behind closed doors -- in the same plush Vienna hotel where the Joint Comprehensive Plan of Action (JCPOA) was hammered out on July 14, 2015.

Under the deal, Tehran agreed to massively scale back production of nuke-making material in return for massive sanctions relief.

But the pact has not eased tensions between Tehran and Washington, which continue to clash over conflicts in Syria and Yemen, where Iran-backed militia hold clout.

US President Donald Trump has been a virulent critic of the nuclear accord signed under his predecessor Barack Obama, calling it "the worst deal ever".

Although Trump has yet to make good on his campaign promise to rip up the agreement, his administration on Tuesday announced a fresh round of non-nuclear sanctions over Iran's ballistic missile programme.

The move came hours after the White House admitted the Islamic republic was complying with the nuclear accord.

Iran responded with its own sanctions and accused the US of trying to "poison the international atmosphere". 

"All members were unanimous in saying that the JCPOA must be preserved and that all sides must fulfill their undertakings," Araqchi said

He said he had expressed his concerns in bilateral talks with the US after Friday's main meeting.

Source: AFP