Insurgent attacks in and around Baghdad killed 21 people Sunday as Iraqi forces began a security sweep of the capital. Iraqi authorities launched the Baghdad operation after a month of insurgent attacks killed 600 people across Iraq. Early Sunday, Iraqi soldiers and police set up checkpoints on the city's outskirts before beginning street-to-street searches. A suicide car bomber killed nine Iraqi soldiers at one of the checkpoints south of the city. Other attacks killed 12 Iraqi police and civilians in and around the capital. The militant group al-Qaida in Iraq posted an internet statement saying its leader, Abu Musab al-Zarqawi, is leading the insurgent response to the Baghdad operation. That statement is the latest of several conflicting statements about Zarqawi and his health recently posted on the group's website.