BAGHDAD (AP)-– Shiite parties that helped propel Iraq's prime minister into power three years ago dumped him Monday as their candidate for re-election, forming a new alliance to contest the January vote.

The move dealt a blow to Nouri al-Maliki's chances to keep his job next year and set the stage for a showdown between competing factions in the Shiite coalition that had dominated Iraq's government since the fall of Saddam Hussein in 2003.
Al-Maliki now faces pressure to make a deal with minority Sunni parties to strengthen his position. Because his Dawa party is relatively small, he has never been able to rely on a loyal political base. Instead, he has developed a reputation as a strong leader by crushing militias loyal to anti-American Shiite cleric Muqtada al-Sadr in Baghdad and in the southern city of Basra.
The Shiite prime minister's efforts to win public confidence by portraying himself as a champion of security have taken a battering in recent weeks. A wave of horrific bombings has called into question the government's ability to protect the Iraqi people two months after most U.S. forces pulled out of urban areas.
In the latest violence, bombs attached to two buses en route from Baghdad exploded less than an hour apart near the mainly Shiite city of Kut on Monday, killing at least 11 people and wounding 20, police and hospital officials said. Local police chief Brig. Gen. Raed Shakir Jawdat said the explosives were detonated with timers.
Monday's political announcement — made with fanfare at a news conference — represents a major realignment.
The new bloc, called the Iraqi National Alliance, will include the largest Shiite party, the Supreme Iraqi Islamic Council, or SIIC, and al-Sadr's bloc.
Al-Maliki, who took office in May 2006 with the blessing of the Supreme Council and the Sadrists, has become increasingly assertive as his popularity has grown with the sharp decline in violence.
His loyalists ousted the Supreme Council from control of the oil-rich southern Shiite heartland in provincial elections earlier this year, raising concern among other Shiite politicians that internal divisions could cost them seats to Sunnis in the upcoming parliamentary elections.
But the unrelenting explosions — including two suicide truck bombings against the foreign and finance ministries that killed scores last week — have weakened his position at a crucial time.
He stayed out of the new alliance because leaders refused to guarantee him the prime minister's spot, officials said. Rumored possibilities for the job include new alliance members ex-Prime Minister Ibrahim al-Jaafari, current Vice President Adel Abdul-Mahdi and even Former Deputy Prime Minister Ahmad Chalabi, a one-time Pentagon favorite.
The realignment does not immediately threaten al-Maliki's position as prime minister, but points to stormy politics in the election campaign and beyond, as U.S. troops begin scaling back their presence.
Supreme Council lawmaker Reda Jawad Taqi said a last-ditch meeting was held Sunday to try to bring al-Maliki into the fold but it failed to overcome the differences.