Bomb explosions struck five offices of political parties in Baghdad overnight, wounding seven people, an Interior Ministry source said on Sunday.

Four of the attacked offices were for secular parties, including one belonging to the Iraqi National Dialogue Front, headed by the prominent banned politician Saleh al-Mutlak, the source told Xinhua on condition of anonymity.

Three of the wounded work for Mutlak's campaign office in Adhamiyah neighborhood in northern Baghdad, the source said.

The attacks came as tensions grew between the parties of the Shiite-led government and nationalist parties after the Accountability and Justice Commission in charge of vetting Saddam Hussein's Baath party members barred 145 candidates from participating in March 7 elections.

The Sunni secular candidates Mutlak and Dhafir al-Ani were leading members of the al-Iraqia List, headed by the former prime minister Ayad Allawi, a Shiite secular, before being barred on Friday.

On Saturday, Iraqia List said it was suspending its election campaign for three days after several of its candidates were among banned politicians from running in the elections over accusation of links to Saddam Hussein's regime.

The halt of Iraqia campaign came as Iraq officially launched campaign for its elections on Friday, while hundreds of pictures and posters of candidates were seen posted on streets in Baghdad and major cities in the country. The campaign is expected to last until March 6.

Iraq is scheduled to hold parliamentary elections on March 7, with around 19 million eligible people, including 1.4 million living abroad in 16 countries, will take part in the elections to elect 325 lawmakers out of over 6,000 candidates for the upcoming parliament.