At least 17 people were killed by explosions in Baghdad and other Iraqi cities on Sunday, Iraqi police and officials said.

Nine people were killed and at least 20 others were also wounded in one of the worst attacks in the Iraqi capital in several weeks, which police said targeted Iraqi Finance Ministry adviser Salman al-Mugotar.

A Finance Ministry source said Mugotar was unhurt in the blast in al-Hurriya Square in Baghdad's Karrada district, but at least two wounded were reported to be his security guards.

Brigadier-General Abdul-Karim Khalaf, a spokesman for the Interior Ministry, said the car that was targeted belonged to Satar Jabar, chief editor of the New al-Bayna newspaper.

He said Jabar was riding in the car but was also unharmed. He gave a lower death toll for the attack.

A Reuters witness at the scene saw two burned corpses in the back of a police truck.

Roadside bombs wounded two people in the Ameen district of southeastern Baghdad, and wounded another two in the Kesra neighbourhood of northern Baghdad.

Rockets or mortar rounds also landed in the Rustumiya neighbourhood of southeastern Baghdad, police said, but there were no details about casualties from that attack.

Iraqi civilian and U.S. military casualties have dropped sharply in the past two months, with the number of reported attacks falling.

The decrease has been attributed to an extra 30,000 U.S. troops, improving Iraqi security forces and the increasing use U.S.-backed neighbourhood police units organized by mainly Sunni Arab tribal sheikhs.

However U.S. and Iraqi officials say Iraq's insurgency and sectarian strife between majority Shi'ites and minority Sunni Arabs, in which tens of thousands of Iraqis have died, could still reignite.

In Baquba, an ethnically mixed and volatile city 65 km (40 miles) north of Baghdad, a roadside bomb targeting a U.S. foot patrol killed at least three children, two of them siblings, and wounded seven people, police said.

In Mosul, 390 km (240 miles) north of Baghdad, a parked car bomb targeting a police patrol killed three people, including a woman, police said. Four policemen were among 16 wounded.

Police said a roadside bomb killed an Iraqi army officer and a soldier and wounded another while they were trying to defuse the bomb in Tikrit, 175 km (110 miles) north of Baghdad.

(Additional reporting by Waleed Ibrahim, Wisam Mohammed and

Mariam Karouny; Writing by Missy Ryan; Editing by Elizabeth Piper)