BAGHDAD - General Ray Odierno took command of U.S.-led
forces in Iraq on Tuesday, faced with the challenge of ensuring
security gains do not unravel at a time when American troop
levels are being reduced.
 

Odierno replaced General David Petraeus at a ceremony
presided over by U.S. Defense Secretary Robert Gates, who said
the two generals had formed an "incredible team" during the
deployment of 30,000 extra U.S. troops to Iraq last year.
 

The towering, shaven-headed Odierno served as the number 2
U.S. commander in Iraq for 15 months until February.
 

"He (Odierno) knows that we are at a pivotal moment -- where
progress remains fragile and caution should be the order of the
day," Gates said in the ornate halls of one of Saddam Hussein's
former palaces that is now part of a giant U.S. military base.
 

While violence has hit four-year lows in Iraq, militants
have still been able to pull off large-scale attacks.
 

A female suicide bomber killed 22 people at a dinner
celebration for police in Diyala province on Monday, hours after
two car bombs killed 12 people in the capital Baghdad.
 

Odierno and Petraeus came together last year to implement a
new counter-insurgency strategy that helped drive violence down,
allowing Iraq to begin seeking foreign investment to rebuild
after decades of war and U.N. sanctions.
 

Petraeus leaves behind a very different Iraq from the one he
faced when he took over in February 2007, when Iraq was on the
brink of all-out civil.
 

"Slowly, but inexorably, the tide began to turn. Our enemies
took a fearsome beating they will not soon forget," said Gates.
 

MANY CHALLENGES
 

But Odierno will still face numerous challenges.
 

On the security front, these include making sure Sunni
Islamist al Qaeda, already significantly weakened, remains on
its knees and unable to incite sectarian bloodshed.
 

Iraq is expected to hold provincial elections either at the
end of 2008 or in early 2009. These will be followed by national
polls in late 2009.
 

Both could be a flashpoint for tensions between Arabs and
Kurds with territorial disputes in the north as well as rival
Shi'ite factions vying for dominance in the south, home to most
of Iraq's vital oil reserves.
 

Iraq's Shi'ite-led government will also soon take control of
Sunni Arab tribal units that joined forces with the U.S.
military to fight al Qaeda. Some analysts fear the tribal units,
which include many former Sunni Arab insurgents, could turn
their guns on the government if their demands are not met.
 

Gates lauded Petraeus in his speech at the ceremony.
 

"You ... dealt the enemies of the United States and Iraq a
tremendous, if not mortal, blow. History will regard you as one
of our nation's great battle captains," Gates said.
 

From October, Petraeus will head the U.S. Central Command,
the headquarters overseeing operations in the Middle East and
beyond, including the war in Afghanistan.
 

The Pentagon will pull 8,000 troops out of Iraq by February,
leaving 138,000 soldiers deployed there. All five extra combat
brigades sent to Iraq last year completed their withdrawal in
July and have not been replaced.
 

Despite the drop in overall violence in Iraq, the Bush
administration has taken a cautious approach to troop cuts and
any decision on a major withdrawal will be left to the next U.S.
president, who takes office in January.
 

Officials and analysts say other factors played a big role
in reducing violence in Iraq, including a decision by former
Sunni Arab insurgents to turn against al Qaeda and a ceasefire
imposed by Shi'ite cleric Moqtada al-Sadr on his Mehdi militia.