The Al Qaeda terrorist group will kill again unless it is stopped, Prime Minister Tony Blair said Tuesday in a speech urging Western nations to support the war in Afghanistan.

Blair issued a rallying cry amid signs of public unease over the air campaign against Afghanistan, saying evidence linking Usama bin Laden to the Sept. 11 terror attacks on the United States was "a flood confirming guilt." Bin Laden's Al Qaeda group and the Taliban regime in Afghanistan are "virtually a merged organization," he said.

"We have a group of people in Afghanistan who are the sworn enemies of everything that the civilized world stands for, who have killed once on a vast scale and will kill again unless stopped," Blair told the Welsh Assembly in Cardiff before leaving on a diplomatic tour of the Middle East.

Blair's tour, shrouded in secrecy due to security concerns, came as British Foreign Secretary Jack Straw was to hold talks in Warsaw, Poland, and Moscow later this week on the global situation.

While a majority of Americans and Britons still back the war, opinion polls have shown a dip in support amid reports of stray U.S. bombs killing Afghan civilians. Islamic countries have also warned that Muslim support could wane if the war is continued through the holy month of Ramadan, which begins in mid-November.

Blair acknowledged public concerns over civilian deaths, the plight of refugees as winter approaches and what will happen after the conflict is over.

"All these concerns deserve to be answered," he said. "No one who raises doubts is an appeaser or a faint heart. We are a democracy, strong enough to have doubts raised even at a time of war, and wise enough, I hope, to be able to respond to them."

But he said the scale of the attacks on New York and Washington, and the thousands of civilian deaths they caused, must not be forgotten as airstrikes enter a fourth week. The Taliban are legitimate targets, he said, and the body of evidence linking the terror attacks to bin Laden and his al-Qaida network is now overwhelming.

"The intelligence evidence, a flow when I first drew attention to it on the third of October, is now a flood confirming guilt," Blair said, in reference to a dossier of evidence his office released more than three weeks ago.

Blair said a failure of resolve among allied governments and their citizens was the only thing that could lose the war.

"They have one hope," he said. "That we are somehow decadent, that we lack the moral fiber or will or courage to take them on; that we might begin, but we won't finish; that we will start then falter; that when the first setbacks occur, that we will lose our nerve. And they are wrong."

Blair warned that Al Qaeda intends to commit further attacks. His spokesman said later that the FBI's statement Monday that terrorists could soon strike the United States or abroad did not signal an imminent attack on Britain.