BAGHDAD: A wave of bombings and shootings hit Iraq during a major Shiite religious commemoration on Wednesday, killing at least 49 people and wounded dozens more, security and medical officials said.

The attacks are the deadliest to hit Iraq since 50 people were killed in Baghdad on March 20 and come during commemorations for the death of Imam Musa Kadhim, the seventh of 12 revered imams in Shiite Islam, which peak late June.

The deadliest attacks occurred in the central Iraq city of Hilla, where two car bombs killed 19 people and wounded 48 others, according to a police captain and doctor Ali al-Khafaji in the city's hospital.

In the Baghdad area, at least 18 people died in a spate of nine bombings and two shootings which also left dozens of people wounded, security and medical officials said.

A medical official said that an attack in Karrada in central Baghdad killed 16 people and wounded 32 others, while another attack in Nahrawan on the outskirts of the city killed two people and wounded eight others.

An interior ministry official meanwhile put the toll from attacks in and around the Iraqi capital at 21 killed and 60 wounded.

Five people were killed in a wave of attacks in Baquba, north of Baghdad.

"There was a series of attacks with nine roadside bombs in different areas on the outskirts of Baquba, which killed four people and wounded seven," a police colonel said.

Gunmen also attacked a house north of Baquba, killing a father and wounding his wife and three children, while a car bomb against a police patrol in the city wounded four police, the colonel said.

A medical source in Baquba hospital confirmed the toll.

In Balad, north of Baghdad, five people were killed and 30 wounded in two car bombs, a police lieutenant colonel said.

The toll was confirmed by a local government official, who said one of the car bombs exploded near the local headquarters of the Shiite endowment.

A car bomb in Al-Azizyah, south of Baghdad, killed two people and wounded at least two others, a police captain and a medical source said.

And a car bomb 10 kilometres (6 miles) north of Karbala in central Iraq wounded 24 people, a health ministry official said.

Another car bomb in the restive north Iraq city of Mosul wounded three people, a police second lieutenant and a medical source at the Hamdaniyah hospital said.

The Shiite majority in Iraq have been a main target of Sunni Arab armed groups since the US-led invasion of 2003 toppled now executed dictator Saddam Hussein's Sunni-dominated regime.

Violence in Iraq has declined dramatically since its peak in 2006-2007, but attacks remain common, especially in Baghdad. A total of 132 Iraqis were killed in violence in May, official figures show.

Wednesday's attacks come during a political row that has seen opponents of Iraqi Prime Minister Nuri al-Maliki mounting an attempt to oust him, but failing due to lack of numbers.

Maliki's opponents have for months accused him of monopolising decision-making and building an army loyal only to him. AGENCIES