Iran on Monday flatly dismissed a call by Saudi Arabia for Gulf states to be consulted on any potential negotiations with the Islamic republic on its nuclear programme.
Saudi Foreign Minister Prince Faisal bin Farhan had on Saturday sought that the kingdom be "fully consulted" on "what goes on vis a vis the negotiations with Iran."
The request was rejected on Monday by Iran's foreign ministry spokesman Saeed Khatibzadeh.
"Everyone is free to talk, but it's better that they do not talk above their level so that they don't embarras themselves," he told reporters.
"Dwelling too much about the place of a mediocre country in the region does not help," the spokesman said in response to repeated questions on the Saudi position.
Khatibzadeh also accused Riyadh of funding extremist ideology and being responsible for many of the "troubles" of the Arab and Islam world, saying the Saudi people "deserve better".
President-elect Joe Biden has signalled he wants the United States to return to the 2015 Iran nuclear deal known formally as the Joint Comprehensive Plan of Action, or JCPOA.
The accord has been on life-support since 2018, when US President Donald Trump withdrew and began reimposing sanctions as part of a "maximum pressure" campaign against the Islamic republic.
Since 2019, Iran has gradually walked back most of its key nuclear commitments in response to the sanctions and what it calls Europe's inability to provide it with the agreement's promised economic benefits.
Tehran has maintained that its measures can be restored if the other parties to the deal carry out their commitments.
Sunni-ruled Saudi Arabia cut diplomatic ties with Shiite Iran after demonstrators attacked its diplomatic missions in the Islamic republic following the execution of a revered Shiite cleric.
The regional rivals are on opposing sides in conflicts from Syria to Yemen.
Animosity between them deepened last year after a series attacks on tankers in the Gulf, which Washington blamed on Tehran despite Iranian denials.
Khatibzadeh reiterated Iran's stance against renegotiating the nuclear accord and said "the JCPOA has already been written".
He also dismissed a recent request by Germany -- which remains party to the accord along with Britain, China, France and Russia -- for a new, broader deal that would include limits on Tehran's ballistic missile programme.
"Iran will neither compromise nor negotiate its national security," Khatibzadeh said.
"We hope Europe knows its place," he added, noting that it "should know that what could not be achieved using maximum pressure will not be achieved through other means either."