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President Bush warned Wednesday that the United States must not lose focus in fighting ruthless killers in Iraq who want that country to devolve into chaos before two key upcoming elections.

Offering remarks in a Rose Garden speech after meeting with his top generals in the War on Terror (search), Bush said terrorists will not win because coalition forces are on the offensive. He added that the coalition now includes more than 100 Iraqi battalians operating with increasing effectiveness.

"The Iraqi troops know their people, they know their language and they know who the terrorists are," he said.

Bush said insurgents are trying to blunt recent successes in the war in Iraq, such as the weekend killing of a top Al Qaeda lieutenant and recent agreement on a draft constitution.

The Pentagon announced Tuesday that the No. 2 Al Qaeda figure in Iraq, Abdullah Abu Azzam (search), was killed in a weekend raid in Baghdad. Abu Azzam was said to be the top deputy of Abu Musab al Zarqawi (search), the most wanted terrorist in Iraq.

"This guy's a brutal killer," Bush said.

Bush said part of the U.S. plan is to prevent insurgents from crossing the borders to escape Iraqi and American forces and to make sure Iraqis know they have the freedom to make decisions about their future. Referring to comments by Gen. George Casey (search), the multi-national force commander in Iraq, Bush said Casey warned of the terrorists' persistence despite the loss of Abu Azzam in the terror network.

"He talked about the nature of an enemy we will face, an enemy that is ruthelss and brutal, an enemy who's got strategic goals and the tactics to achieve those goals," he said. "We're determined to defeat the enemy."

Casey and other top members of the president's military team are in Washington Wednesday. Casey and Gen. John Abizaid (search), chief of Central Command, will meet with lawmakers on Capitol Hill later Wednesday. Bush urged congressional members to meet with the generals.

"The support of Congress for our troops and our mission is important and Americans need to know about the gains we have made in recent weeks and months, they need to know the way we're adapting our tactics, and the way we're changing our strategies to meet the needs on the ground," Bush said.

Bush also discussed upcoming challenges for Iraq, most notably the referendum in mid-October to approve the constitution.

In the lead-up to the Oct. 15 election, special security issues are taking precedence. Insurgent violence has been known to increase immediately before major events like last year's transfer of sovereignty and national elections last January. Abu Azzam was credited with the mounting the escalation in homicide bombings that have killed nearly 700 people in Baghdad since April.

Bush called the events ahead a challenge, but also an opportunity.

Since Sept. 11, 2001, the president has scored consistently well in public opinion polls on his leadership in the War on Terror, but as the situation in Iraq drags on, with little variation in the monthly number of U.S. dead, polls have shown an erosion of support. This month, the number of U.S. servicemen killed has passed 1,900.

But some of the loss in public support in America has come because many say they don't think the coalition forces are being forceful enough to stop insurgents. Without some form of calm in Iraq, natives there are also going to grow more weary, said one analyst.

"There has been a reaction against the United States for being the 'instigator,' that's a quote, for allowing Zarqawi to take root," counter-terrorism expert Steve Emerson told FOX News.

The Associated Press contributed to this report.