Iran pledged today to help establish security in Iraq and visiting Iraqi Prime Minister Nuri al-Maliki vowed his country would not be used to harm Iran.
Some Iraqi officials and the United States have accused Iran of trying to destabilise Iraq by financing, training and equipping Iraqi militias. Iran blames the instability on the presence of US troops in Iraq.
During Mr Maliki's three-day visit to the Islamic state, Iranian officials have insisted Tehran supports peace and security in the neighbouring country.
"Iran will always be on the side of the popular government of Iraq," the state news agency IRNA quoted First Vice-President Parviz Davoudi as saying in talks with Maliki on Sunday.
"Helping the establishment of security in Iraq has always been one of Iran's main policies."
To counter Shia Iran's growing influence in Iraq, Washington has been trying to persuade Iraq's Sunni-ruled Gulf Arab neighbours to offer more support to Maliki's government, by forgiving debts and opening diplomatic missions in Baghdad.
Mr Maliki's government, dominated by Shias and Kurds, follows a fine line in its relations with Iran, seeking support from Tehran while Iraqi officials accuse it of supporting Shi'ite militias in Iraq.
The student news agency ISNA quoted Mr Maliki as saying in Tehran: "Iraq's territory cannot be used by any country for harming Iran's security."
An Iraqi spokesman said last week Mr Maliki wanted to discuss evidence of Iranian intervention in Iraq and the two countries' overall relationship.