The dead in Tikrit, north of Baghdad, were Salaheddin television's chief news editor, a copy editor, a producer, a presenter and the archives manager, the officers said.
Two of the bombers blew themselves up during the attack, and security forces killed the other two when they stormed the building in the assault, in which five Salaheddin employees were wounded.
Last week, militants attacked the Tikrit city council headquarters, and a council member and two police were killed.
The country is currently experiencing the worst violence against journalists in years, with 12 killed in attacks since October 5.
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Other violence today killed 17 people, as officials said unrest in Iraq was being fuelled by the Syrian civil war.
Mortar rounds struck an army base in the Abu Ghraib area west of Baghdad, killing a brigade commander, three other officers and two soldiers, security officials said.
Two days earlier, five senior officers, including a divisional commander, and 10 soldiers were killed during an operation against militants in the mainly Sunni western province of Anbar.
Violence has reached a level not seen since 2008, when Iraq was just emerging from a brutal period of sectarian killings.
Yesterday, the United States called for regional leaders to work to cut funding and recruitment for two jihadist groups -- the Islamic State of Iraq and the Levant and Al-Nusra Front -- saying foreign fighters were going to Syria and then carrying out attacks in Iraq.
ISIL operates in both Syria and Iraq, while the Al-Nusra Front is based in Syria but has also been linked to Iraq.