BAGHDAD — Two suicide bombings killed at least 24 people and injured as many as 100 others north of Baghdad on Tuesday, the latest attacks to take aim at Iraqi security forces and local volunteers credited with helping to bring about a major drop in violence.
The attacks in Baiji and Baqubah shattered a period of relative calm as Muslims marked the four-day Eid al-Adha festival, which ended Monday for Shiites and Saturday for Sunnis. The government extended the holiday until Tuesday, when the Christian minority celebrated Christmas.
Insurgents have turned their guns on the volunteers, many of whom once fought alongside them. Northern Iraq has suffered many such attacks as insurgents pushed out of Baghdad and al-Anbar to establish footholds in the region. Baqubah residents said leaflets have been circulated urging them to kill the volunteers.
In Tuesday’s worst attack, a suicide bomber blew up a truck at a checkpoint in Baiji, site of a major oil refinery 125 miles north of the capital. Police and hospital officials said at least 25 people were killed and 75 injured.
The blast ignited cooking gas that was being sold nearby, police said.
“What kind of Islam is this?” asked Ali Arkan, who was in his bed when a large piece of glass smashed into his shoulder. “Surely this is not the Islam that we know. These days we are living are very holy days for Muslims and Christians. Those people have no respect and no relationship with either Christianity or Islam.”



