BELGRADE, Montana (AP) -- Republican Sen. Conrad Burns, whose recent comments have stirred controversy, says the United States is up against a faceless enemy of terrorists who "drive taxi cabs in the daytime and kill at night."

During a fundraiser Wednesday with first lady Laura Bush, the three-term Montana senator talked about terrorism, tax cuts and the money he has brought to his state. Burns is one of the more vulnerable Senate incumbents, facing a tough challenge from Democrat Jon Tester.

He has drawn criticism in recent weeks for calling his house painter a "nice little Guatemalan man" during a June speech. Burns, whose re-election campaign is pressing for tighter immigration controls, also suggested that the man might be an illegal immigrant. The campaign later said the worker is legal.

Burns, 71, also had to apologize after confronting members of a firefighting team at the Billings airport and telling them they had done a "piss-poor job," according to a state report. In July, the Hotshot crew had traveled 2,000 miles from Staunton, Virginia, to help dig fire lines for about a week around a 143-square-mile wildfire east of Billings.

At the campaign event with Bush, Burns talked about the war on terrorism, saying a "faceless enemy" of terrorists "drive taxi cabs in the daytime and kill at night."

Bush described Burns as a strong advocate for Montana farmers and families.

"In Washington, Senator Burns is a respected voice on the issues facing rural communities in Montana and across the nation," Bush told Burns supporters.

She also said Burns has been important in helping the president on key initiatives, such as tax cuts, and has supported the troops fighting in Iraq and the war on terror.