A suicide car bomb killed at least 15 people and wounded more than 30 at the entrance to a town northeast of Baghdad on Monday morning, security sources have told Al Jazeera.

There was no immediate claim of responsibility for the blast outside Khalis, about 80km from the capital, but the Islamic State of Iraq and the Levant group (ISIL) regularly attacks security forces and civilian areas.

A police officer at the scene told Reuters news agency that most of the victims died inside their vehicles while waiting to enter the town.

"We still have charred bodies inside many vehicles, including a minibus packed with women and children," the police captain said, requesting anonymity.

Hospital sources told Reuters the death toll was expected to rise given the extent of critical injuries.

The blast came a day after a suicide bombing claimed by ISIL, which is also known as ISIS, killed at least 15 people in Baghdad's Kadhimiyah neighbourhood.

Haider al-Abadi, Iraq's prime minister, has come under pressure to improve security since a suicide attack claimed by ISIL earlier this month killed 292 people in central Baghdad, one of the largest attacks of its kind since the US-led invasion in 2003.