In an apparently coordinated double bombing, two blasts occurred in a street with many restaurants near the government compound in the main city of Nineveh province, 390 km (240 miles) north of the capital Baghdad.
Police said the first bomb targeted an army water tanker truck and then when rescuers came running to help the victims, the second vehicle detonated.
One of those killed and several of the wounded were military personnel, police said.
"I heard a huge explosion ... when I went out to see what had happened, there was another big explosion. I saw dozens of people lying in the street. I couldn't make out who was killed and who was wounded," restaurant owner Mone'm Mahmoud, 33, told Reuters. The blasts shattered the windows of his restaurant.
Mosul is regarded as Sunni Islamist al Qaeda's last remaining urban base in Iraq after the group was kicked out of many parts of Baghdad and western Anbar province by U.S. troops allied with local Sunni Arab tribal militias in 2007.
At the end of April, eight people were killed and 19 wounded when a suicide bomber blew himself up in the city.
Although violence has fallen in Iraq since the height of the sectarian slaughter in 2006-2007 following the 2003 U.S.-led invasion that toppled Saddam Hussein, gun and bomb attacks against Iraqi security forces still occur daily.
There are fears that attacks may be increasing ahead of the planned withdrawal at the end of the year of the remaining 47,000 U.S. troops.
"This kind of attack is aimed at creating the impression that there is no stability in the province," Deldar Zebari, deputy head of the Nineveh Provincial Council, told Reuters.
Nineveh is on the frontline of a potentially explosive dispute over land and power between Kurds in their semi-autonomous northern enclave and Iraq's majority Arabs.
Multiple bomb blasts killed more than 40 people in cities west and north of Baghdad earlier this month in apparently coordinated attacks that were claimed by al Qaeda's Iraqi wing.
On Monday, five U.S. soldiers died in a rocket attack on a base in Baghdad claimed by a Shi'ite militia.
This week, U.S. President Barack Obama's pick to be the new defence secretary, outgoing CIA chief Leon Panetta, said he expected Iraq to eventually ask Washington to keep U.S. troops in the country beyond the end-2011 withdrawal deadline.