A suicide bomber targeted the home of a senior Iraqi intelligence officer north of Baghdad on Saturday, killing three people, while three more died in other attacks, officials said.

The bomber detonated a small tanker truck at the home of police Brigadier General Ismail al-Juburi, a senior officer for Nineveh province, killing his son, nephew and sister-in-law -- and wounding 21 others, police and a doctor said.

It was not immediately clear if Juburi was present at the time of the attack, which took place in the Al-Sharqat area.

Suicide bombings, usually carried out by Sunni militants, including those linked to Al-Qaeda, are a relatively rare type of attack in Iraq. Roadside bombs, magnetic "sticky bombs" on vehicles and shootings are more common.

However, four suicide bombers struck in various parts of northern Iraq on Wednesday, killing four people.

In the other attacks on Saturday, a roadside bomb killed two soldiers and wounded two others in Nineveh province, an army officer and a doctor said.

And in Tikrit, also north of the capital, gunmen killed Sabhan al-Ajili, the owner of a money exchange shop, police and a doctor said.

Violence in Iraq has fallen from its peak at the height of the sectarian conflict in 2006 and 2007, but attacks remain common, killing more than 200 people in each of the first four months of this year.