A US Marine Corps a M1A1 Abrams tank in Iraq

General John Abizaid told a group of reporters on Tuesday the current level of U.S. troops in Iraq - more than 140,000 - will remain unchanged at least until the middle of next year. At that time, the general said the Defense Department will then re-evaluate.

The general described the current number of troops as "prudent" to achieve the needed military effect in Iraq. And General Abizaid added that if more forces are needed to stem rising violence - particularly in the Iraqi capital, Baghdad - the U.S. military will do it. That could mean extended tours of duty for U.S. troops already on the ground. In the past, some top military officials had hinted at plans to reduce troop levels in Iraq beginning this year.

The Pentagon has said there are now 147,000 troops in Iraq due to an overlap of units rotating into and out of the country.

Nico Pitney is a research associate for the Center for American Progress - a Washington-based public policy institute. He says General Abizaid's message represents a big change by the Bush administration.

"I think it's a major announcement," said Nico Pitney. "Particularly because it is a major shift from previous statements that top military officials have made. Several months ago, they were claiming that by the end of this year, there would only be 100,00 or 110,000 U.S. troops in Iraq, and the fact that now we are going to be sticking up to 140 [thousand], and possibly even more, signals that conditions on the ground there are not going as well as expected."

Analyst Pitney says U.S. forces are serving an important function - they are providing stability - but they are no longer the main target of attack in Iraq.

"I think we are seeing that the violence is not directed at U.S. troops," he said. "It is directed at the sectarian opponents - Shias are attacking Sunnis and vice versa. And that problem is not going to be solved by U.S. troops."

But Pitney believes the fighting in Iraq is at such a stage that it is time for U.S. leaders to devote more attention to other areas.

"I think we ought to begin this year redeploying forces to some critical hot spots that are under-resourced right now; namely, Afghanistan which is suffering from a resurgence of the Taleban," added Nico Pitney. "You will have U.S. forces remaining in Iraq, not on the frontlines but continuing the job to train Iraq security forces - a job that has moved along slowly, but which is nowhere near complete. By the end of 2007, we ought to have these Iraqi forces trained, leave a small number of special forces in there after 2007.

Analyst Pitney says removing U.S. forces from Iraq will put the United States in a better position to address another problem. He says the readiness level of the U.S. military is as low as it has been in decades. With fewer troops in Iraq, the United States will be better able to handle crises that may occur in other parts of the world.