Iraq hosts an estimated 3,000 members of the People's Mujahedeen Organisation of Iran (PMOI) who are living in exile in Iraq and based in a former military camp near Baghdad airport.
"Considering that PMOI members are criminals who have assassinated more than 17,000 Iranians, one of our requests to Iraq's justice chief is to extradite them to Iran, so that they could be held accountable for their crimes," Larijani said, according to Fars news agency.
He was speaking at the end of a meeting with the visiting Iraqi chief justice, Medhat al-Mahmud, media said.
In March, Iran's ambassador to Iraq, Hassan Danaeifar, was quoted as told the Mehr news agency that Tehran was ready to pardon 423 PMOI members, after investigation showed they are not guilty of any crimes.
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The leftwing PMOI was founded in the 1960s to oppose the shah of Iran.
The group set up camp in Iraq during Saddam Hussein's war with Iran in the 1980s, but was disarmed after the US-led invasion of Iraq in 2003 toppled Saddam.
Today's Shiite-majority and Iran-friendly government in Baghdad is eager to see it move elsewhere.
In April Iranian Justice Minister Mostafa Pour-Mohammadi travelled to Iraq to sign several memoranda of understanding, including the extradition of criminals.
In 2012, the United State removed the PMOI group from its terror blacklist, in a move strongly condemned by Iran.