Six policemen have been killed and four others wounded in an overnight attack on a checkpoint near the northern Iraqi city of Mosul, police have said.
A spokesman said gunmen in four cars ambushed the checkpoint in Qayyara, 360km (225 miles) north of Baghdad, at around 0130 (2130 GMT).
Later, an Iraqi army officer and his father were shot dead by gunmen who broke into their home in central Mosul.
The mainly Sunni Arab area has seen an upsurge in violence in recent months.
Correspondents say the increased violence appears to be a consequence of the surge offensive launched by US-led forces in and around Baghdad earlier this year.
Many Sunni insurgent groups are believed to have reacted by transferring their bases of operations to other provinces in the north.
Police Brigadier Abdul Karim Jabouri said he believed the assailants in Qayyara were members of the Islamic State of Iraq, an umbrella group that includes al-Qaeda in Iraq.
In other violence, one person was killed in an "indirect fire attack" on Camp Victory, the US military base near Baghdad International Airport.
The US military said the person killed was neither American nor Iraqi. Eleven US soldiers were injured in the attack, the military added.