CAIRO, Egypt, AP -Al-Qaida”s No. 2 embraced the London suicide bombings Thursday, warned Britain that more destruction lies ahead and promised tens of thousands of U.S. casualties in Iraq in a brazen assertion of the terror group”s global reach.

Ayman al-Zawahri also renewed terror threats to other countries with troops in Iraq and Afghanistan, claiming they had shunned Osama bin Laden”s offer last year of a truce if foreign forces left the battleground.

In the tape, parts of which were broadcast by Al-Jazeera, al-Zawahri made no direct claim that al-Qaida carried out the July 7 attacks in the British capital, but sought instead to blame the carnage on Prime Minister Tony Blair”s decision to deploy and keep troops in Iraq. Britain maintains 8,500 forces mainly in southern Iraq.

&#34Blair has brought to you destruction in central London, and he will bring more of that, God willing,&#34 al-Zawahri said.

President Bush dismissed al-Zawahri”s threat, saying, &#34We will stay on the offense against these people. They”re terrorists and they”re killers and they will kill innocent people … so they can impose their dark vision on the world.&#34

In London, Blair”s Downing Street office declined to comment.

Jeremy Bennie, a terrorism analyst for Jane”s Defense Weekly, said al-Zawahri appeared to be trying to put an al-Qaida stamp on the July 7 attacks on the London transit system. The bombings killed 56 people, including four attackers.

&#34He has tacitly taken responsibility by claiming al-Qaida is in control of the situation, even as most people aren”t really sure bin Laden and al-Zawahri still are capable of organizing such an attack,&#34 Bennie said by telephone.

Thursday marked the seventh time al-Zawahri has used videotapes or audiotapes to speak for al-Qaida since the Sept. 11, 2001, attacks in the United States. The latest appearance followed the Egyptian physician”s pattern of issuing threats of further death and destruction if the United States and its allies in Iraq and Afghanistan refuse to withdraw troops from the region, including Saudi Arabia — home to two of Islam”s holiest shrines.

Al-Zawahri issued the fresh threats with a Kalashnikov rifle propped against a woven cloth background that moved with the wind and showed the sunlight, suggesting the scene was filmed outdoors. He wore a white robe and black turban and emphatically wagged his finger while speaking.

The black turban — a change from the white turban he has worn in past videos — is &#34a sign that it”s time of war,&#34 said Montasser el-Zayat, an Egyptian attorney who defends Islamic radicals and who spent three years in prison with al-Zawahri. The prophet Muhammad and his followers wore black turbans during their invasions in the Arabian Peninsula, he said.

Al-Zawahri is &#34exploiting the whole atmosphere following London and Sharm el-Sheik explosions to carry out the sort of instigation that propels more operations,&#34 el-Zayat said. At least 64 people were killed in the July 23 attacks in the Egyptian Red Sea resort of Sharm el-Sheik.

As the Iraqi insurgency led by bin Laden”s Jordanian comrade Abu Musab al-Zarqawi continues to kill Iraqis and Americans, al-Zawahri promised more savagery.

&#34What you have seen in New York and Washington, you Americans, and the losses you see in Afghanistan and Iraq — despite all the media blackout — are merely the losses from the initial clashes,&#34 he said.

&#34If you go on with the same policy of aggression against Muslims, you will see, God willing, what will make you forget the horrible things in Vietnam,&#34 he said.

&#34There is no exit from Iraq except in immediate withdrawal. Any delay in taking that decision means nothing but more dead, more losses,&#34 he said. &#34If you don”t leave today, certainly you will leave tomorrow, but after tens of thousands of dead and double the number of disabled and wounded.&#34

Al-Zawahri threatened other nations who have sent troops alongside U.S. forces in Iraq and Afghanistan, saying they &#34will harvest the fruits of their cooperation soon, God willing.&#34

He also called for Arab militaries, intellectuals and businessmen to start working to get rid of &#34corrupt&#34 regimes in the Middle East and &#34start prepare for change, starting now, whatever it takes of time or effort.&#34

Bennie said al-Zawahri may have been using the video as a vehicle for reissuing an offer of a truce.

&#34This seems to say you have another chance to pull out and you won”t be hit again,&#34 the analyst said, declaring the statement coercive and not credible.

He noted that most observers believed the March 11, 2004, Madrid train attacks, which killed 191 people, were designed to push Spaniards to vote for the Socialist opposition in elections three days later. In the voting, the Conservative government which had sent troops to Iraq was swept from power. The new government ordered Spanish troops to return home.

&#34That didn”t prevent a foiled attempt to bomb a high-speed train carrying a thousand people after the election. And members of the cell still had the wherewithal to blow themselves up when cornered,&#34 Bennie said.

Taahir Hoorzook, of the media relations department in Al-Jazeera, said the broadcaster received the new tape Thursday at one of its offices, though he would not specify its location.

The tape is about five minutes long and Al-Jazeera aired only 10 percent of it, he said. The rest was rhetoric that &#34we found not newsworthy,&#34 Hoorzook said.