Smoke billows after bomb blast at Baghdad market  Tuesday Aug. 8, 2006

At least 20 people in Baghdad have been killed in a series of attacks in the Iraqi capital.

Iraqi authorities said two bombs exploded minutes apart Tuesday at the main Shurja market in central Baghdad, killing 10 and injuring 69 others.

The latest violence underscores the security crisis facing Iraqi Prime Minister Nouri al-Maliki as he attempts to halt what many analysts see as a slide towards civil war.

Much of the violence has been blamed on sectarian militias.

About 6,000 additional Iraqi troops and 3,500 U.S. troops are being deployed in the Iraqi capital to help stem the violence.

In another development, the U.S. military says the Fourth Iraqi Army division has officially assumed the lead in its area of responsibility from the 101st U.S. Airborne division. The area includes the cities of Kirkuk and Tikrit.