Speaking in a meeting with Ayatollah Sistani in Najaf, Shamkhani also commended the role of Shiite religious leaders in maintaining Iraq’s national unity.
Ayatollah Sistani in June issued a fatwa (religious decree) which called on all Iraqis to take up arms against the terrorists of the so-called Islamic State in Iraq and the Levant (ISIL).
Nearly 1.5 million Iraqis, consisting of people of different social strata, volunteered to join battles against the al-Qaeda-linked militants.
Shamkhani further referred to the recent election of Iraq’s parliament speaker as "a significant step," and hailed the political consensus for the formation of legal structures in the Arab country.
The Iraqi parliament elected moderate Sunni politician Salim al-Jabouri as new speaker on Tuesday.
The position of speaker is the first of three leadership posts which Iraq's Shiite, Sunni and Kurdish politicians were seeking to agree, three months after a parliamentary election.
The other two posts are the presidency and the prime minister.