Ties between the two neighbours have lately been strained by tensions over Iran carrying out cross-border strikes against exiled Kurdish opposition groups it accuses of fomenting unrest at home.

Responding to a pledge by Sudani that he would not allow Iraqi territory to be used to undermine Iran's security, Khamenei said: "unfortunately, this is currently occurring in some parts of Iraq".

Sudani's meeting with the supreme leader followed talks with Iranian President Ebrahim Raisi during which they identified fighting "terrorism", mutual security and economic cooperation as key priorities.

Sudani was on his first official visit to Tehran after becoming prime minister last month, following a year-long tussle between political factions over forming a government following an October 2021 general election.

"From our perspective and that of the Iraqi government, security, peace, cooperation and regional stability are very important," Raisi told a joint news conference.

Sudani said that "our government is determined not to allow any group or party to use Iraqi territory to undermine and disrupt Iran's security."

Since nationwide protests erupted in Iran more than two months ago, officials have accused Kurdish opposition groups exiled in northern Iraq of stoking the unrest and the Islamic republic has repeatedly launched deadly cross-border strikes.

Strikes targeting Iranian-Kurdish groups in Iraq's autonomous Kurdistan region resumed this month, even after Iraq's federal government summoned Iran's ambassador in late September to complain about cross-border missile and drone hits that killed at least seven people.

On Tuesday Khamenei urged Sudani to take a tougher line.

"The only solution is for the Iraqi government to extend its authority" to regions that are undermining Iran's security, he said, referring to Iraqi Kurdistan.

Iraq has announced in the past week that it will redeploy federal guards on the border between Iraqi Kurdistan and Iran, rather than leaving the responsibility to Kurdish peshmerga forces -- a move welcomed by Tehran.

On Tuesday, Sudani said that Iraqi and Iranian national security advisers would hold consultations to "establish a working mechanism for on-the-ground coordination to avoid any escalation".

He also thanked Iran for its continued deliveries of gas and electricity, which have been in short supply in Iraq.

Raisi said banking, finance and wider business topics were also discussed and that talks between the two allies "will help to resolve bilateral problems".