WASHINGTON (Reuters) - President George W. Bush sought on Saturday to dispel concerns about the readiness of U.S.-trained Iraqi security forces, declaring himself "encouraged" even though his top generals say the number of battalions that can fight insurgents without help has dropped.

"I'm encouraged by the increasing size and capability of the Iraqi security forces. Today they have more than 100 battalions operating throughout the country, and our commanders report that the Iraqi forces are serving with increasing effectiveness," Bush said in his weekly radio address.

Bush has said that creating Iraqi security forces able to defend their own country is a prerequisite to an eventual withdrawal of U.S. forces from Iraq.

One of the few measures the Pentagon has offered the public to judge the capabilities of Iraqi security forces has been the number of battalions that can go into combat with insurgents without the help of the U.S. military.

During congressional testimony on Thursday, Gen. George Casey, top U.S. commander in Iraq, and Gen. John Abizaid, top U.S. commander in the Middle East, said the number of such battalions had dropped since July to one from three, out of the roughly 100 Iraqi battalions.

Defense Secretary Donald Rumsfeld sought to play down the new estimate on Friday, saying, "Its relevance is minimal."

Bush also sought to repair any damage. He said on Saturday the U.S. military and its allies are "constantly adapting our tactics to the changing tactics of the terrorists."

"We're training more Iraqi forces to assume increasing responsibility for their country's security," Bush added.

More than 1,900 U.S. troops have been killed in Iraq since the U.S. invasion in March 2003, and the American public is expressing growing uneasiness over the war in opinion polls.

A USA TODAY/CNN/Gallup Poll published last week found 63 percent of respondents said some or all of the U.S. troops in Iraq should be withdrawn, and a record-high 59 percent said the invasion was a mistake.

Bush cited the killing of al Qaeda's Abu Azzam as a sign the U.S. strategy in Iraq was defeating a violent insurgency.

As a result of what he called an "increasing number of more capable Iraqi troops," Bush said the U.S. military was keeping a better hold on cities after offensives against insurgents are complete. He said Iraqi units are left behind to prevent the "terrorists" from moving back in.

He also pointed to the decision this week to turn over security responsibility for one of Iraq's largest cities, Karbala, to Iraqi soldiers, as a sign of progress.

He warned there would be more violence before an October vote on a new constitution. "More difficult and dangerous work still lies ahead. The terrorists have a history of escalating their attacks before Iraq's major political milestones," Bush said.

Commentary:
It's time to seriously consider whether Bush is fit for duty. After reading this article, can anyone say he is?