Four bombings in three districts in Baghdad killed at least 23 people and wounded dozens on Sunday, as the U.S.-led security crackdown entered the third month.

In the bloodiest attack, two car bomb went off within minutes in a shopping area in western Baghdad on Sunday morning, killing at least 15 people and wounded more than 50 others, an Interior Ministry source told Xinhua.

Minutes after the twin blasts, a mortar round landed in the same area in al-Shurta al-Rabia neighborhood, apparently part of a coordinated attack.

Around midday, three people were killed and ten others injured when a bomb went off inside a mini-van near a courthouse in Kadhmiya neighborhood in northern Baghdad. Initial report said the bomb was hidden in a bag in the mini-van.

Hours later, the fourth bombing rocked Karradah neighborhood in central Baghdad, killing at least five people and injuring ten others.

"A car bomb parking near Abu-Afeef sweets shop in an intersection in Karradah neighborhood detonated at about 3 p.m. (GMT 1100) while an Iraqi police patrol was passing by," a source from Interior Ministry said.

In Mosul, 400 km north of Baghdad, at least four people were killed and up to 20 others injured when two car driven by suicide bombers exploded outside an Iraqi military base, local police said.

In Taji, 20 km north of Baghdad, one British soldier died and another five were injured when two UK Puma helicopters crashed early Sunday.

UK Ministry of Defense Secretary Des Browne said in a statement that "sadly, two personnel have died and one is very seriously injured. Three others have suffered more minor injuries. All were UK personnel."

"Initial reports indicate that the crash was an accident and not as a result of an attack by insurgents. An investigation is underway," it said.

The latest surge in violence came as the security plan in Baghdad entered the third month, which is widely seen as the last chance to restore stability in the country.

However, so far the country is still plagued by sectarian violence and unabated terrorist attacks.