On Tuesday, some 20,000 people, mostly Shia Muslims, converged on Nasiriyah to protest the first talks in Iraq on a post-invasion government.

Iraq’s main Shia Muslim opposition group, the Supreme Council for the Islamic Revolution in Iraq, organized the protest against control of the talks.

The BBC reported that the Shia are concerned Washington is preparing to install a pro-US puppet government.

The Shia leadership in Najaf distributed instructions to mosques across the country to form defense committees and control what’s happening in the streets.

Prior to the invasion, rhetoric within the Pentagon and State Department pinned Shia Muslims–who were brutally suppressed by Saddam’s Sunni Muslim minority–as reliable allies in the campaign.

But during the invasion, US forces met with heavy military resistance in Shia-dominated cities in southern Iraq. And now Shia Muslims are strongly resisting US influence in reshaping the country.

As US occupation forces turn a blind eye to unrelenting violence and looting in cities throughout Iraq, friction between Sunni and Shia Muslims continues to escalate.

The prospect of a civil war between Sunni and Shia Muslims threatens further instability in a country plagued by lawlessness.

• As’ad AbuKhalil, professor of political science at University of California, adjunct professor at UC Berkeley. Author of 'Bin Laden, Islam and America's New War on Terrorism.’