Violence in Iraq, including shelling in a rebel-held city and an attack targeting Shia pilgrims, has killed more than 30 people in 24 hours, officials have said.

It came as officials counted ballots from the April 30 general election, the first since US troops withdrew in late 2011, and amid a protracted surge in nationwide unrest that has sparked fears of a return to the large-scale sectarian killing sprees of 2006-2007.

In Fallujah, just a short drive west of Baghdad, shelling in southern areas of the city killed 11 people and wounded four others, Ahmed Shami, a doctor, said.

It was not immediately clear who was behind the bombardment, which began on Saturday evening and continued into Sunday.

In a sign of the significant power of anti-government fighters, all of Fallujah and parts of Anbar provincial capital Ramadi, farther west, have been out of government control since early January.

The crisis in Anbar, which shares a long border with conflict-hit Syria, erupted in late December when security forces dismantled Iraq's main Sunni Arab anti-government protest camp just outside Ramadi.

Shia pilgrims attacked

North of Baghdad, a bombing and shooting targeted a bus carrying Shia pilgrims on Saturday evening, killing 11 people and wounded 21 others, police and a doctor said.

The pilgrims were returning from Samarra when a roadside bomb exploded on the outskirts of the town of Balad and gunmen opened fire on the bus.

The worshippers had been participating in commemorations marking the death of Imam Ali al-Hadi, the 10th of 12 imams who are key to the Shia Muslim faith.

Also on Saturday evening, police found the bodies of eight family members shot dead inside their home in a predominantly Sunni area southeast of Baghdad.

It was unclear why the family had been targeted or who killed them.

More than 3,000 people have been killed already this year, according to an AFP tally based on security and medical reports.

Source: Agencies