Kadhemi is the first foreign leader to visit the ultra-conservative Raisi, and brought along a "high level political and economic delegation," Iran's official IRNA news agency said.

Television showed the Iraqi premier welcomed by a guard of honour, before immediately beginning a meeting that IRNA said touched on "questions of mutual and international interest".

The two leaders are expected to hold a news conference later Sunday, state broadcaster Iribnews reported.

As Iran's neighbour to the west, Iraq has sought a mediating role between Tehran and Arab nations.

Since April, it has tried to broker talks with Saudi Arabia to soothe tensions between the regional rivals.

An Iraqi source had said Friday that Kadhemi would raise energy cooperation and Iranian-Saudi relations in the talks.

Other hot topics include Iraq's six-billion-dollar debt to Iran, after shortages pushed it to turn to its neighbour to cover one-third of its gas and electricity needs.

This summer Iran suspended exports for several days over the outstanding amount.

Sunday's meeting is also expected to address the issue of visas for Iranian pilgrims travelling to Shiite holy sites in Iraq.

Iraqi authorities late Thursday announced new quotas for foreign pilgrims for the Arbaeen pilgrimage in the Shiite shrine city of Karbala later this month.

Kadhemi's office said that 60,000 Iranian pilgrims would be allowed to attend, up from 30,000 previously announced.

Arbaeen marks the end of the 40-day mourning period for the killing of Imam Hussein, grandson of the Prophet Mohammed, by the forces of the caliph Yazid in 680 AD.

The number of visas issued to foreign pilgrims permitted has dropped sharply in the past two years due to the coronavirus pandemic.