The talks in the Iraqi capital earlier this month, which have not been confirmed by either capital, were held at the level of officials not ministers and aimed at restoring relations severed five years ago, an Iraqi official and a Western diplomat told AFP in Baghdad.

Tehran has neither confirmed nor denied the reports saying only that it has "always welcomed" dialogue with Saudi Arabia. Riyadh has flatly denied them.

Foreign ministry spokesman Saeed Khatibzadeh said Zarif's visits to Qatar and Iraq are "in the framework of developing bilateral ties (and) regional and trans-regional talks."

The Baghdad talks, brokered by Iraqi Prime Minister Mustafa al-Kadhemi, remained secret until the Financial Times reported last weekend that a first meeting had been held on April 9, with another planned for shortly after.

An Iraqi government official confirmed the meeting to AFP, while a Western diplomat said he was "briefed in advance that talks would happen" with the "purpose to help broker a better relationship between Iran and Saudi and decrease tensions".

The meetings came amid talks in Vienna between Iran and major powers on the mechanics of a US return to a landmark 2015 nuclear deal abandoned by president Donald Trump.

The talks must also address Iran's own return to full compliance with the deal, after it suspended its implementation of several key provisions in protest at Trump's reimposition of sweeping economic sanctions.

Tehran has rejected calls by Riyadh to be involved in the nuclear negotiations, but has repeatedly stated its readiness to conduct a regional dialogue.

Tehran and Riyadh are on opposing sides in conflicts from Syria to Yemen and have had strained relations since the kingdom cut diplomatic ties in 2016.

Some Gulf states have followed Saudi Arabia in taking a tough line on Iran.

But Qatar has maintained warm relations despite the appeals of Saudi Arabia and its allies, which cited it as one of the reasons for imposing a blockade on the gas-rich emirate in 2017.

That rift now appears to have healed after Qatar was invited to a meeting in Saudi Arabia in January at which it was brought back into the regional fold.