BAQUBA, Iraq A suicide bomber killed 22 people and wounded 60 in a crowded election campaign tent in the Iraqi city of Baquba on Saturday, police and medics said.
A decade after the U.S.-led invasion, Iraq is still struggling with political instability and violence that in recent weeks has killed at least 10 candidates who had planned to run in forthcoming local elections.
The vote is due to be held across the country later in April, but has already been delayed in two Sunni Muslim-majority governorates due to security concerns.
The suicide bomber attacked a gathering for Sunni candidate Muthanna al-Jorani in Baquba, 65 km northeast of the capital Baghdad. Jorani himself escaped unscathed.
Candidates in Iraq often put up tents during campaigning as a venue to meet potential voters and explain their policies.
"First a hand grenade targeted the tent next to the one I was in," a 23-year-old wounded in the attack told Reuters by telephone from hospital. "People were running in every direction and bits of chair were scattered all over the place.
"A few seconds later, an explosion took place in the same tent."
Most of the 10 candidates killed earlier belonged to the Sunni-backed Iraqiya bloc led by former Prime Minister Iyad Allawi, a secular Shi'ite politician.
Sectarian and ethnic tensions have risen since the U.S. withdrawal from Iraq in December 2011, inflamed by the conflict in neighbouring Syria, where mainly Sunni rebels are trying to oust President Bashar al-Assad, who is backed by Shi'ite Iran.
Tens of thousands of Sunnis have staged street protests in Anbar and other provinces against Iraq's Shi'ite-led government, which they accuse of marginalising their minority sect.
Anbar, which borders Syria, was almost entirely controlled by al Qaeda at the peak of Iraq's insurgency and Sunni militants are again finding strongholds there, security experts say.
The United States has urged the government to reconsider its decision to suspend elections in Anbar and Niniveh governorates, saying it is vital that all Iraqis vote simultaneously.
"We are very concerned by the decision ... to postpone provincial elections in two provinces, Anbar and Nineveh, on the stated grounds of security," said a U.S. diplomat.
Attacks in Iraq are less common than during the Sunni-Shi'ite slaughter that reached a climax in 2006-07, but shootings and bombings still occur almost daily.
Iraq is home to a number of insurgent groups including the al Qaeda affiliate, Islamic State of Iraq, linked by the United States to the militant Nusra Front which is fighting in Syria.
(Additional reporting by Raheem Salman; Writing by Isabel Coles; Editing by Alistair Lyon)