The White House says the large explosion that ripped through a hotel in central Baghdad Wednesday comes at a time of testing in Iraq, but will be met with resolve.

White House Spokesman Scott McClellan says the Bush administration has no details about who is responsible for the Baghdad blast.

"This is a terrible terrorist attack on innocent civilians," he said. "Our thoughts and prayers are with the victims and with the families. This remains a time of testing in Iraq. The stakes are high. The terrorists know the stakes are high, but they will not prevail. We will meet this test with strength and resolve."

Mr. McClellan says democracy is taking root in Iraq, and there is no turning back from the creation of a free and peaceful country, which he says will be a major blow to terrorism.

President Bush was briefed on the blast before leaving for a luncheon meeting on Capitol Hill.

Mr. McClellan says the attack will not deter the Bush administration from continuing to make what he calls "important progress" in Iraq.