Iraq's security forces launched its biggest offensive against insurgents in Baghdad on Sunday, involving 40,000 Iraqi troops, a defense ministry official said.

Operation Lightening was launched to crack down on a new wave of violence that had left more than 650 people dead across the country since a Shiite-dominated government was formed on April 28.

Iraqi soldiers and police blocked all entrances of Baghdad and erected some 675 checkpoints in and around the capital while others conducting a houses-to-house search. Hundreds of suspects were arrested and weapons seized, a source in the defense ministry told Xinhua on condition of anonymity.

On Thursday, Defense Minister Sadoun al-Dulaimi said that Baghdad will be divided into seven areas in eastern Baghdad, and 15 in western Baghdad, and more than 40,000 security members will take part in the operation.

Source: Xinhua