Mosul, Iraq  - Four people died in attacks near the northern Iraqi city of Mosul on Monday, police said, in the latest in string of clashes and bombings in the area.

Three civilians were killed and four others were wounded by stray bullets when Iraqi police officers and unidentified gunmen exchanged fire in the al-Salam district east of Mosul, a source in the city's police department told Deutsche Presse-Agentur dpa on Monday.

In a separate incident, an Iraqi police officer was killed and two others were wounded when a roadside bomb exploded as they patrolled the Hay al-Zahur district north of Mosul, roughly 400 kilometres north of Baghdad.

The attacks came shortly after Iraqi Prime Minister Nuri al-Maliki called for national reconciliation following three bombings on Sunday.

"National reconciliation must be an open door, through which all who believe ... in the political process can enter," al-Maliki told a gathering of branches of Iraq's prominent al-Abid tribe on Monday.

"We must pass through that door, lest we return to violence, murder, racism, and communal strife," the Iraqi prime minister said.

His speech followed a surge in violence across the country. At least 31 people were killed and 64 were injured in three bombings in Baghdad and Mosul on Sunday.

In Sunday's first bombing, Baghdad's deadliest in months, at least 28 people were killed and 54 were injured by a suicide bomber on a motorcycle outside a police recruitment centre.

Later on Sunday, three people died and 10 more were injured in twin car bombings in different districts of western Mosul.

On February 20, Iraqi security forces in Mosul began a push, dubbed "Operation New Hope," to arrest militants from al-Qaeda in Iraq.

Security forces have made more than 100 arrests from so-called "hot" neighbourhoods in Mosul, but militants have retaliated with increasingly regular attacks against the police. (dpa)