U.S. President Barack Obama says the United States is on track to remove all of its troops from Iraq by the end of 2011.  But he notes that difficult times lie ahead.  Mr. Obama spoke after talks at the White House with Iraqi Prime Minister Nouri al-Maliki.

President Obama said the United States is in the midst of a full transition in its relations with Iraq.

He said that as American forces are withdrawn, the two countries are forging a new relationship built on far more than security concerns.

But Mr. Obama warned there will be "tough days" ahead - noting that while violence is down in Iraq, there are still those who want to sabotage the progress already made.

"There will be attacks on Iraqi security forces and the American troops supporting them," said President Obama. "There are still those in Iraq who would murder innocent men, women and children.  There are still those who want to foment sectarian conflict.  But make no mistake, those efforts will fail."

The president said the Iraqi people have already rejected what he calls "the forces of division and destruction".  He added that American troops remain ready to help.

But there have been reports of Iraqi restrictions on the roughly 130,000 U.S. forces in the country, following their withdrawal from cities and towns last month.

At a joint appearance in the White House Rose Garden with Prime Minister al-Maliki, President Obama downplayed the problem as one of differences over strategy and tactics.  He said that overall, things are going well.

"What we have seen is that the violence levels have remained low," said Mr. Obama. "The cooperation between U.S. forces and Iraqi forces has remained high and we have every confidence that we will continue to work together cooperatively and make adjustments where necessary."

In his remarks to reporters, the president also stressed the need for national unity efforts in Iraq to intensify.

Prime Minister al-Maliki said he shares that objective. 

"We will work very hard not to allow any sectarian behavior and opportunity to flourish," said Prime Minister al-Maliki. "We will work on a national plan where all sons of Iraq and all daughters of Iraq are equal in their contribution and their services.  They will be unified by Iraq, they will not be divided by other elements."

Mr. al-Maliki came to Washington after talks in New York with United Nations officials on ending the sanctions imposed on Iraq after its 1990 invasion of Kuwait.  President Obama said he supports the move.

"It, I think, would be a mistake for Iraq to continue to be burdened by the sins of a deposed dictator," he said.

The sanctions, imposed when Saddam Hussein ruled Iraq, include reparations to Kuwait that currently amount to five percent of Iraq's oil revenue.