Iran's state-run news agency, IRNA, says Iranian and Iraqi security officials have signed a border security pact in the Iranian capital, Tehran.
The report says Iranian and Iraqi border commanders reached the agreement during their first joint meeting Friday.
The report says the two sides agreed on terms for patrolling the shores of the Shatt al-Arab waterway, which marks the southern-most section of Iran and Iraq's border.
The United States says weapons are being smuggled from Iran into Iraq where they are used by Shi'ite militias.
Along the northern Iranian-Iraqi border Thursday, Kurdish sources reported Iran had resumed shelling inside Iraq's Kurdish region. There was no word on any casualties.
In recent months, Iranian forces have clashed with Kurdish rebels in northwestern Iran.
The insurgents are believed to be linked to Turkey's separatist Kurdistan Workers Party, PKK.