MOSUL: Attacks in Baghdad and north Iraq killed five security personnel and a civilian on Sunday, officials said, part of a nationwide surge in violence that authorities have failed to stem.

The shootings and bombings were the latest in months of unrelenting bloodshed, Iraq's worst since 2008, and come despite wide-ranging operations targeting militants and tightened security.

In northern Nineveh province, a suicide bomber drove through a police checkpoint and detonated a car rigged with explosives, killing two policemen and wounding three others and a civilian who was nearby, security and medical officials said.

The bombing struck the Shia Turkmen city of Tal Afar.

Also in Nineveh, gunmen opened fire on an army checkpoint in the provincial capital Mosul, killing two soldiers. And an election commission worker was gunned down elsewhere in Mosul.

In south Baghdad, a roadside bomb targeting a police patrol killed a police major and wounded three policemen, officials said.

Violence so far this year has left more than 5,450 dead, the country's worst violence since 2008, and Prime Minister Nuri al-Maliki has appealed to the US for greater cooperation in the fight against militancy.

In addition to major security problems, the Iraqi government has 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.