Attacks across Iraq, the deadliest of which struck the main northern city of Mosul, left seven people dead and 50 wounded Sunday, the latest in a months-long surge in bloodletting.

The violence comes ahead of annual Shiite commemoration ceremonies, when Sunni militants often mount attacks more frequently, and as Iraq grapples with continuing bloodshed despite wide-ranging operations targeting insurgents and tightened security measures.

The spike in unrest has spurred Prime Minister Nuri al-Maliki to appeal for greater cooperation with the United States in combatting militancy, while Turkey on Sunday offered to help as well.

Bombings and shootings struck a half-dozen cities across Iraq on Sunday, but the deadliest of the violence hit Mosul.

A suicide bomber blew himself up at an army recruitment centre in the predominantly Sunni Arab city, one of Iraq's most violent, killing two people and wounding seven others, while a bombing at a popular restaurant killed two more and left a dozen wounded.

Two others were killed and 10 wounded in a series of shootings across the city.

A female civil servant was also shot dead in Baghdad, while bombings in the southern cities of Basra, Hilla, Samawa and Diwaniyah left more than 20 people wounded.

Attacks have surged in recent months. Although no group has claimed all of the violence, much of it has been attributed to Sunni militants linked to Al-Qaeda who oppose Iraq's Shiite-led government.

The bloodshed is part of the worst unrest since 2008, when Iraq was emerging from a brutal Sunni-Shiite sectarian war.

It comes shortly after the start of the Islamic new year and as Shiites converge on the shrine city of Karbala, south of Baghdad, to commemorate a key figure in Shiite Islam, a period during which Sunni militants often try to target them and the security forces.

In addition to major security problems, authorities have failed to provide adequate basic services such as electricity and clean water, and corruption is widespread.

Political squabbling has paralysed the government, while parliament has passed almost no major legislation in years.