Thousands of Iraqi Shi'ites took to the streets of the country's second largest city Friday to show their support for the new draft constitution.

The rally in Basra was organized by the two main Shi'ite political parties - The Supreme Council for the Islamic Revolution in Iraq and the Dawa Party - in advance of the October 15 national referendum.

Demonstrators also condemned Wednesday's stampede in Baghdad that killed hundreds of Shi'ite pilgrims during a religious procession. Funerals continued Friday for the victims, as the government began an investigation into the tragedy.

Meanwhile, in the Sunni Arab heartland of western Iraq, protesters demonstrated against the constitution, which they fear will lead to the physical break-up of Iraq.

And the U.S. military says three American soldiers have been killed in central Iraq since Wednesday.