The executions, carried out by hanging, were the first to be confirmed since January 23 and brought to at least 44 the total number of people put to death so far this year.
Among those executed were three men -- Hadi Hassuni, Abdul Hassan al-Majid and Farukh Hijazi -- who were convicted in April 2011 over the April 1994 murder of Sheikh Taleb al-Suhail al-Tamimi, and termed agents of the ousted Saddam regime.
She was elected to the Council of Representatives in March 2010 polls as part of Prime Minister Nuri al-Maliki's slate, but is now an independent MP.
Tamimi, head of the Banu Tamim tribe, fled to Beirut with his family after a Baath Party coup in 1968 and later attempted his own coup against Saddam Hussein, but was gunned down outside his home in the Lebanese capital on April 14, 1994.
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Lebanon severed its ties with Iraq in the aftermath of the killing, and it arrested five Iraqi diplomats and one Lebanese accomplice over the assassination.
The other four diplomats later returned to Iraq only to flee after the 2003 US-led invasion that ousted Saddam.
The four other people executed today were convicted on terror charges, the justice ministry said.
Iraq has faced widespread criticism from diplomats, analysts and human rights groups who say that due to a flawed justice system, those being executed are not necessarily guilty of the crimes for which they were sentenced to die.
UN chief Ban Ki-moon urged Iraq to halt executions on a visit to Baghdad in January.
The country executed at least 169 people last year, according to an AFP tally based on statements from the justice ministry and reports from officials.