They were the second round of talks in less than two months, following a discreet meeting in Geneva last November between Tehran and the three European powers, Britain, France and Germany, known as the E3.

The meeting was largely shrouded in secrecy, with few details revealed about the topics discussed or the venue of the talks.

"The Iranian Deputy Foreign Minister Majid Takht-Ravanhchi and his counterparts from the E3 met on Monday evening," Iran's ISNA news agency reported.

"They discussed issues of mutual interest, including negotiations for lifting sanctions, the nuclear issue and the worrying situation in the region," it added without elaborating.

Prior to the discreet meeting, the German foreign ministry told AFP that the talks "are not negotiations," while Iran similarly emphasised that they are merely "consultations".

The talks, scheduled for Monday and Tuesday, will cover a "wide range of topics," Iran's foreign ministry spokesman Esmaeil Baqaei said during a weekly press briefing.

"The primary objective of these talks is to remove the sanctions" on Iran, he noted, adding that Iran was also "listening to the topics that the opposite parties want to raise."

ISNA reported that Takht-Ravanhchi will meet on Tuesday separately with the European Union's Enrique Mora in Geneva.

- 'Breaking point' -

On Thursday, France's foreign ministry said the meeting was a sign that the E3 countries "are continuing to work towards a diplomatic solution to the Iranian nuclear programme, the progress of which is extremely problematic".

The talks come with Iran's nuclear programme under renewed focus in light of Trump's imminent return to the White House on January 20.

During his first term, Trump had pursued a policy of "maximum pressure", withdrawing the US from a landmark nuclear deal which imposed curbs on Iran's nuclear programme in return for sanctions relief.

Tehran adhered to the deal until Washington's withdrawal, but then began rolling back its commitments.

Efforts to revive the 2015 nuclear pact have since faltered and European officials have repeatedly expressed frustrations over Tehran's non-compliance.

Last week, French President Emmanuel Macron said the acceleration of Iran's nuclear programme is "bringing us very close to the breaking point". Iran later blasted the comments as "baseless" and "deceitful".

In December, Britain, Germany and France accused Tehran of growing its stockpile of highly enriched uranium to "unprecedented levels" without "any credible civilian justification."

"We reiterate our determination to use all diplomatic tools to prevent Iran from acquiring a nuclear weapon, including using snapback if necessary," they added.

- 'Significant non-performance' -

The snapback mechanism -- part of the 2015 deal, known as the Joint Comprehensive Plan of Action (JCPOA) -- allows signatories to reimpose United Nations sanctions on Iran in cases of the "significant non-performance" of commitments.

The option to trigger the mechanism expires in October this year, adding urgency to the ongoing diplomatic efforts.

The International Atomic Energy Agency (IAEA) nuclear watchdog says Iran has increased its manufacturing of enriched uranium such that it is the only non-nuclear weapons state to possess uranium enriched to 60 percent.

That level is well on the way to the 90 percent required for an atomic bomb.

Iran maintains that its nuclear programme is solely for peaceful purposes and denies any intention to develop atomic weapons.

It has also repeatedly expressed willingness to revive the deal.

President Masoud Pezeshkian, who took office in July, has favoured reviving that agreement and called for ending his country's isolation.

In a recent interview with China's CCTV, foreign minister Abbas Araghchi also expressed willingness "to engage in constructive negotiations".

"The formula that we believe in is the same as the previous JCPOA formula, namely, building trust on Iran's nuclear program in exchange for lifting sanctions," he added.