By Caren Bohan

FORT BLISS, Texas (Reuters) - President Barack
Obama declared the U.S. combat mission in Iraq officially over
Tuesday but said he would not take a "victory lap" because a
lot more work remained to be done inside the country.

Obama, thanking troops in Texas before delivering an
evening address to the nation, said Iraq now had the
opportunity to create a better future for itself, and the
United States, as a result, was more secure.

"I wanted to come down to Fort Bliss mainly to say thank
you. And to say, welcome home," he told troops, who shouted the
traditional Army "Hooah" back to him in greeting.

"I'm going to make a speech to the nation tonight," Obama
said. "It's not going to be a victory lap. It's not going to be
self-congratulatory. There's still a lot of work that we've got
to do to make sure that Iraq is an effective partner with us."

The White House says the removal of all but 50,000 U.S.
troops and the declaration of the end to the combat phase shows
Obama is fulfilling a campaign promise he made in 2008 to pull
out of Iraq.

Obama hopes that message will resonate with Americans ahead
of the Nov. 2 elections in which his Democrats are struggling
to keep their dominance in the U.S. Congress.

But high unemployment and slowing economic growth have
eclipsed the war as the top issue in voters' minds, much as the
economy did in 2008 when Obama prevailed over Republican John
McCain in the presidential election.

Ben Rhodes, White House deputy national security adviser,
said Obama would talk about the U.S. economy in the context of
the drawdown from Iraq.

"He feels it's very important to refocus resources that
we've been spending abroad over the last several years into
investing in our economy and our long-term competitiveness here
at home," Rhodes told reporters on board Air Force One.

White House spokesman Robert Gibbs previewed the same
economic theme in U.S. media interviews earlier in the day.

"The nation he truly wants to rebuild is the nation that he
lives in, the United States of America," Gibbs said on ABC
television. "We gain our strength abroad from our prosperity
here at home. There are steps that we have to take here to
continue our recovery to make sure that people are getting put
back to work," he said.

The address, scheduled for 8 p.m. EDT, will be
Obama's second from the Oval Office. The president used the
same high-profile venue in June to discuss his administration's
response to the Gulf of Mexico oil spill.

Obama called former President George W. Bush, who launched
the war in 2003, during his flight.

SENSE OF URGENCY, NOT MISSION ACCOMPLISHED

As Obama prepared to deliver his speech, U.S. Vice
President Joe Biden flew into Iraq to assure Iraqis the United
States is not abandoning them. He met with Prime Minister Nuri
al-Maliki and President Jalal Talabani.

Biden's talks took place amid a political deadlock almost
six months after an inconclusive election in March over forming
the next government.

"Iraq should move forward with a sense of urgency," Rhodes
said. "It is time to get down to some of the core issues."

The White House is aware that Obama cannot afford to come
across as too triumphant. To do so could evoke comparisons to
Bush's May 2003 speech aboard an aircraft carrier. In front of
a "Mission Accomplished" banner, Bush announced that major
combat operations were over, a move that was seen as a huge
misstep after violence soared later.

More than 4,400 U.S. soldiers have died in Iraq since the
U.S.-led invasion in 2003 to topple Saddam Hussein.

"Al Qaeda in Iraq is beaten, but not gone," Defense
Secretary Roberts Gates said Tuesday. "This is not a time
for premature victory parades or self-congratulations, even as
we reflect with pride on what our troops and their Iraqi
partners have accomplished."

Obama, who opposed the Iraq war, rode a wave of anti-war
sentiment that boosted his support within his Democratic Party
during the 2008 campaign.

When he took office in January 2009, the U.S. military
presence in Iraq was 140,000 troops and it reached a high of
around 170,000 under the surge ordered by Bush.

The roughly 50,000 U.S. soldiers still in Iraq are moving
into an advisory role in which they will train and support
Iraq's army and police.

The effective change on the ground will not be huge because
the U.S. military has already been switching the focus toward
training and support over the past year. Obama has promised to
pull all U.S. troops out of Iraq by the end of 2011.

Ahead of the speech, Republicans criticized Obama for what
they say is a failure to acknowledge the success of Bush's
troop surge in bringing down violence in Iraq. Obama had
opposed the 2007 troop increase.

Obama has set July 2011 as the date for a beginning of a
drawdown of U.S. forces in Afghanistan and he hopes the example
of Iraq will reassure his Democratic supporters that he can
keep his word.

(Writing by Jeff Mason; Additional reporting by Alister Bull
and Deborah Zabarenko; editing by Vicki Allen)