Two suicide bombers, one in a car and the other wearing an explosive vest, have killed 22 people and wounded 26 in a market in a Shia district in the northern Iraqi city of Tal Afar.
Police in the regional capital Mosul said the bombs had exploded in a market, near an outdoor vehicle sales lot.
Tal Afar, close to the Syrian border, was for a time a stronghold of Sunni insurgent groups linked to al-Qaeda.
It has for the past year been held up as an example of successful counter-insurgency operations by the US military.
Meanwhile, an indefinite curfew remains in place in the Iraqi capital, Baghdad, after what has been described as the worst attack on the city since the US-led invasion of 2003.
Hospital sources have said the death toll from yesterday's wave of car bombings in Sadr City has risen to at least 202, with another 256 wounded.
These were followed by attacks on some Sunni areas.
Iraq has closed its two main airports, in Baghdad and the southern city of Basra, as well as southern sea ports.
The bombings are expected to deepen the rift between the two warring communities.
Iraqi Prime Minister Nuri al-Maliki urged calm but said the Baghdad attacks posed a grave threat to the country's fraternity.
