President Bush warned Wednesday that there may be an upsurge of violence in the weeks before a referendum in Iraq on a new constitution, but added,  "Our troops are ready for it."

The president and members of his administration sought to reinforce their main message that the United States will not draw down its forces, and will continue building Iraq's military and police in the battle against insurgents.

U.S. officials,  including Defense Secretary Donald Rumsfeld and top military commanders, have been on Capitol Hill over the past week briefing lawmakers as part of the administration effort to raise the level of confidence about the direction of the Iraq effort.

White House spokesman Scott McClellan says the president wants to make sure that Congress understands the stakes in Iraq:

"I think Congress understands the importance of succeeding in Iraq," Mr. McClellan says. "They have shown a strong commitment to what we are working to
achieve there, and the President is greatly appreciative of that. It's also important to keep members of Congress informed about what our
strategy is and how we are adapting to defeat the enemy. 

However, the president faces continuing criticism from congressional Democrats who assert there is no clear plan for prevailing in Iraq, or getting out.

A small number of Republicans have joined Democrats supporting a bipartisan resolution calling on the president to announce a plan for beginning the withdrawal of American forces from Iraq.

Congressman Walter Jones, who broke with the House Republican leadership earlier this year on Iraq, recalls a statement in 1999 by George W. Bush when he was governor of Texas, urging then President Clinton to put forward a plan for withdrawing U.S. forces from Kosovo.

"That is all we are doing with this bipartisan resolution, Republican and Democrat.  We are saying to the president, we are asking you to do the same thing that you asked President Clinton to do in 1999," Mr. Jones says.

Supporters of the resolution have managed to gather backing from only about 60 House members, most of them Democrats.

However, they were joined at a Capitol Hill news conference by retired Lieutenant General William Odom, a former director of the National Security Agency.