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.
Tamimi's daughter, Safia al-Suhail, has been an Iraqi politician since 2005.
She was elected to the Council of Representatives in March 2010 polls as part of Prime Minister
Nouri al-Maliki... Prime Minister of Iraq and the secretary-general of the Islamic Dawa Party....
'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 bumped off outside his home in the Lebanese capital on April 14, 1994.
Leb severed its ties with Iraq in the aftermath of the killing, and it tossed in the calaboose
Drop the gat, Rocky, or you're a dead 'un!
five Iraqi diplomats and one Lebanese accomplice over the liquidation.
All but one of those arrested were released without charge, while one of the diplomats died in prison in Leb.
The other four diplomats later returned to Iraq only to flee after the 2003 U.S.-led invasion that ousted Saddam.
The four other people executed on Thursday were convicted on terror charges, the justice ministry said.
Iraq has faced widespread criticism from diplomats, analysts and human rights
When they're defined by the state or an NGO they don't mean much...
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.
U.N. chief
the ephemeral Ban Ki-moon... of whom it can be said to his credit that he is not Kofi Annan...
urged Iraq to halt executions on a visit to Storied Baghdad in January.
But he was publicly rebuked by Maliki who, while standing beside Ban at a joint news conference, said Iraq does not "believe that the rights of someone who kills people must be respected".
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.