Three bombs have killed at least 14 people across Iraq, officials said.

A bomb hidden in a cart exploded outside a school in the northern city of Mosul on Tuesday, killing four people, including two children and wounding 12 others, police said.

A suicide car bomber killed at least five people and wounded 25 near a checkpoint in Tal Afar in northern Iraq, according to police and hospital officials.

An Iraqi officer supervising work at the joint army-police checkpoint said
the blast sent "a ball of fire" toward the security forces, and panicked car passengers next to the sight abandoned their vehicles to look for shelter.

A roadside bomb also struck an Iraqi army convoy in Hilla, south of Baghdad, killing five Iraqi soldiers, a police official said.

"It hit the first vehicle. The whole thing exploded and burned to the ground," Ali al Jubouri, an eyewitness, told Reuters news agency.

Opposing security pact

The attacks came a day after a string of blasts killed more than 30 people
in Baghdad and Mosul, underlining the challenges facing Iraqi security forces as they prepare to take responsibility from US troops.

According to a security pact passed by the Iraqi parliament last week, US troops will withdraw from Iraqi towns by mid-2009 and leave the country completely by the end of 2011.

The attacks can be interpreted as signals of rejection to the security pact, Alaa al Taie, Interior Ministry official, said.

"We read these bombings as messages. The first message is: 'We are still here'. The second is: they reject the accord. They want to create an atmosphere of fear."