Updated

President Bush on Tuesday condemned the deadly truck bombing at U.N. headquarters in Baghdad, calling the attackers "enemies of the civilized world."

Speaking from his Texas ranch, Bush said he had spoken by phone with the U.S. administrator in Iraq, L. Paul Bremer (search), and U.N. Secretary General Kofi Annan (search) about the attack "and about the vital work in Iraq that continues."

• Video: President Bush Comments on the Attack

Several members of the U.S. Congress were in Baghdad touring military sites when the explosion happened — and were scheduled to tour the U.N. facility sometime later in the day. None was hurt. They were have to held discussions with Sergio Vieira de Mello (search), the chief U.N. official in Iraq, who was injured in the attack.

Those who carried out the attack are testing America's will to combat terrorism, Bush said, and are finding across the world that "our will cannot be shaken."

"These killers will not determine the future of Iraq," the president said in a statement at his ranch. "Every sign of progress in Iraq adds to the desperation of the terrorists and the remnants of Saddam's brutal regime."

The vacationing Bush had cut short a golf game and returned to his ranch to monitor developments after talking by phone on the golf course with his national security adviser, Condoleezza Rice.

Earlier, Bush had voiced pleasure over the capture of Saddam Hussein's vice president, pledging to continue going after Saddam loyalists who don't want democracy to take root in Iraq.

Bush said he and Annan discussed "the personal loss the U.N. has suffered." At least 15 people were reported killed and 40 wounded.

"By their tactics and their targets, these murderers reveal themselves once more as enemies of the civilized world," Bush said. "The civilized world will not be intimidated."

In Iraq, Bremer rushed to the scene of the bombing as soon as he learned of it, a spokesman said.

"My message is that the coalition has undertaken a noble cause ... to secure the peace here," said Bremer, standing near the rubble left from the bombing. "There will be ups and downs, there will be days like today ... But there is absolutely no question that the coalition intends to stay the course."

The hastily arranged statement by Bush, delivered from a hangar on his ranch property, was a little over four minutes long. The president, having changed into a jacket, white dress shirt and red tie from his golf outfit and appearing somber, took no questions.

Accompanying him were two top aides, deputy chief of staff Joe Hagin and deputy national security adviser Stephen Hadley (search).

Bush's calls to Bremer and Annan were made once he had returned to the ranch from the golf course.

Earlier, Bush gave reporters an upbeat assessment of U.S. forces' efforts in Iraq, noting that Taha Yassin Ramadan (search), vice president under Saddam, was handed over to U.S. forces in Mosul on Tuesday. He was No. 20 on the U.S. list of most-wanted Iraqis.

Asked if the capture made him hopeful that Saddam himself would soon be nabbed, Bush said: "We'll find him and we'll bring him to justice."

Iraq is on course to self-governance and peace, Bush said, and terrorists want to interrupt that. "Every sign of progress in Iraq adds to the desperation of the terrorists, and the remnants of Saddam's brutal regime," Bush said.

"They're the enemies of the Iraqi people," Bush said. "They're the enemies of every nation that seeks to help the Iraqi people."

In Washington earlier, Secretary of State Colin Powell telephoned Annan to express sympathy and concern and to volunteer help.

Sen. Edward Kennedy, D-Mass., who serves on the Senate Armed Services Committee, immediately condemned the bombing.

"It cannot deter our nation from working with the international community to secure the peace, rebuild Iraq, minimize the burden on our troops, and deliver on the promise of democracy for the Iraqi people," Kennedy said.

Other House and Senate members — including Sen. John McCain, R-Ariz., Rep. Harold Ford, D-Tenn., Sen. Maria Cantwell, D-Wash., and Rep. Jim Kolbe, R-Ariz. — were in Baghdad touring military sites when the explosion happened. None of them was injured, officials said.

"It's a heavy day and a heavy moment but I must say, the resilience and the spirit of our soldiers are unbroken," Rep. Harold Ford, D-Tenn., said on CNN.