Baghdad ? Iraq’s parliament approved a three-year timetable for the withdrawal of U.S. troops Thursday, a pact that supporters call a path to sovereignty and opponents say could be used to keep Americans on Iraqi soil indefinitely.

The pact is the first step taken by Iraqi legislators toward ending the U.S. presence in their country since the American-led invasion in March 2003. It is expected to be ratified by Iraq’s three-person presidency council.

The vote, held above the din of detractors shouting, “No!” and bashing books and binders on desks, followed intense negotiations among the nation’s Sunnis, Shiites and Kurds that portend fierce political battles.

Shiite Prime Minister Nouri al-Maliki will be held to promises of political reform made to Sunnis in exchange for “yes” votes. Kurds could use the promises to press their own demands for autonomy from a central government they see as too strong. And hard-liners loyal to Shiite cleric Muqtada al-Sadr — who opposed the pact, fearing it will allow for an open-ended American presence — have warned of renewed violence against U.S. forces by Shiite militiamen.

Of the 198 lawmakers present, 149 raised their hands in favor of the “Status of Forces Agreement,” or SOFA.

To win backing from the main Sunni Arab blocs, al-Maliki’s ruling Shiites and their Kurdish allies approved a resolution agreeing to consider a “wish list” rooted in Sunni complaints of political sidelining and persecution.

The demands range from amnesty for detainees — many of them Sunnis — held since the U.S. invasion to the incorporation of the mainly Sunni paramilitary group known as the “Sons of Iraq” into government security forces or other jobs.

Rasheed Azzawi, a member of the main Sunni bloc, Tawafiq, admitted there was no guarantee the issues would be resolved. But Azzawi said it “will bind the sides morally” to take action beyond mere words.

The Sunnis could face problems of their own. They also demanded, and got, promises of a public referendum on the SOFA in July.

If voters reject it, Iraq’s government would have to cancel the accord or seek changes to it, possibly leading to a pullout of U.S. forces earlier than the Dec. 31, 2011, deadline.

That would leave Sunnis without the extra protection the United States offers against the Shiite-led government and security forces.

Al-Maliki’s government, however, has portrayed the deal as a surefire path to sovereignty, and President George W. Bush said in a statement posted by the White House that the vote “affirms the growth” of democracy in Iraq.

The pact requires combat troops to leave Iraqi cities, towns and villages by June 30, 2009, as the first step toward total withdrawal.