Three members of Iraq's security forces, including two senior officers, were killed in renewed violence on Tuesday after a wave of attacks a day earlier stoked fears of a revival of sectarian war.
The attacks, all of which were in and around the main northern city of Mosul, came a day after bombings and shootings, most of which targeted security forces, killed 78 people and wounded more than 250.
Monday's unrest was the latest in a surge in bloodshed that, coupled with a long-running political stalemate, has sparked concern Iraq is falling back into the brutal communal bloodshed that blighted it in 2006 and 2007.
Four separate roadside bombs in Mosul and nearby Qaiyarah on Tuesday left two army lieutenant colonels and a policeman dead, and five other members of the security forces wounded, officials said.
No group has claimed responsibility for the latest violence, but Sunni militants linked to Al-Qaeda have in the past launched coordinated nationwide bombings in a bid to undermine confidence in the security forces and the Shiite-led authorities.
Security officials meanwhile said on Tuesday they were carrying out a massive hunt for Al-Qaeda-linked bases in restive Diyala province, just north of Baghdad in central Iraq.
Army Lieutenant General Abdulamir al-Zaidi said three militants had been killed and 14 others arrested as part of the operation, which one army colonel said, on condition of anonymity, involved some 40,000 members of the security forces.
The unrest comes amid a surge in attacks in Iraq, with violence in May pushing the month's death toll to its highest level since 2008.
There has been a heightened level of unrest since the beginning of the year, coinciding with rising discontent among the Sunni Arab minority that erupted into protests in late December.
The outgoing UN envoy to Iraq Martin Kobler has warned the violence is "ready to explode".