A suicide bombing on Saturday killed a senior Iraqi intelligence officer and two guards near the main northern city of Mosul, while other blasts left two more dead, officials said.
The attacks were the latest in an uptick in violence that comes as Iraq grapples with nearly two months of anti-government protests and a political crisis.
Brigadier General Aouni Ali, the head of the country's main intelligence academy, and two of his guards were killed in the bombing outside his home in Tal Afar, near Mosul, police and a doctor said.
Also north of Baghdad, a judge was killed by a magnetic "sticky bomb" attached to his car in the village of Sulaiman Pak, according to security and medical officials.
Ahmed al-Bayati, a Sunni Arab who is now a judge handling civil cases, had previously received threats while he was working as an anti-terror investigator, and had to pay kidnappers a $150,000 ransom after his son was snatched last year.
Elsewhere, a roadside bomb killed an army lieutenant and wounded two other soldiers in Heet, northwest of the capital.
No group claimed responsibility for the blasts, but Sunni militants linked to Al-Qaeda often target security forces and government officials in a bid to push Iraq back to the sectarian bloodshed that blighted it from 2005 to 2008.
Iraq has seen a rise in attacks in recent weeks, with January the deadliest month since September, according to an AFP tally.
Levels of violence remain markedly lower than during the peak of the sectarian war in 2006 and 2007, however.