U.S. defense officials say the United States will maintain about 152,000 troops in Iraq until the country holds its constitutional referendum on October 15.  That is 12,000 more troops than senior generals have previously indicated.

The operations director for the Joint Chiefs of Staff, Brigadier General Carter Ham, provided the figure during a news conference on Thursday.

"There are about 152,000 U.S. [troops] in Iraq today," said Mr. Ham.  "That's pretty much the force that will be there for the referendum."

The general's information updates a statement made early last month by the number two U.S. commander in Iraq, Lieutenant General John Vines.  He said there were about 138,000 U.S. troops in Iraq and that only 2,000 additional troops would be needed to help provide security for the referendum. 

The 2,000 figure was repeated last week by the top coalition commander in Iraq, General George Casey, and he compared it to the request he made for 12,000 additional troops for the Iraqi election in January.  General Casey said the need for fewer extra U.S. troops this time was evidence of the increased capabilities of the Iraqi security forces.

Senior officials downplayed the difference between the plan for 140,000 troops and the current level of 152,000, saying such adjustments are made all the time, depending on the specific needs of commanders.  But at Thursday's briefing, General Ham also said that the number of insurgent attacks has been increasing in recent months, partly because of the coming referendum, and the national elections expected in December.

"We have seen, overall, an increase in the number of attacks," he noted.  "That shouldn't be too terribly surprising as we look toward the political events that are about to occur.  We expected that there would be some increase."

General Ham expressed specific concern about support for the insurgents that comes across Iraq's borders with Iran and Syria.  He said the support includes people, money and equipment, but he could not say whether there is official assistance from the Iranian or Syrian governments.  The general said the coalition and Iraqi forces are working to get control of the border areas and the smuggling routes inside Iraq.