Claiming responsibility for the July 7 London blasts, al Qaeda's second-in-command Ayman al-Zawahiri has threatened new attacks against Western countries similar to those that rocked Britain.

"The lands and interests of the countries that took part in the aggression against Palestine, Iraq and Afghanistan are targets for us," Zawahiri said in a videotape aired by Qatar-based al Jazeera on Thursday night.

The videotape in which Zawahiri hailed the London [Images] 'conquest' as similar to that in Madrid last year and the United States in September 2001, also showed footage of one of the London suicide bombers, Mohammad Sidique Khan, who outlined the reasons for his action.

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It was the first explicit claim of responsibility for the blasts, which claimed 56 lives, by the terrorist group headed by Osama bin Laden.

"I talk to you today about the blessed London battle, which came as a slap to the face of the tyrannical, crusader British arrogance," al Zawahri said. "It's a sip from the glass that the Muslims have been drinking from."

"This blessed battle has transferred like its glorious predecessors in New York, Washington, and Madrid the battle to the enemies' land, after many centuries of the battle being on our land and after (Western) troops have occupied our land in Chechnya, Afghanistan, Iraq and Palestine."

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"Just as they made rivers of blood flow in our countries, we will make volcanoes of anger erupt in their countries," Osama bin Laden's right-hand man said.

"We warned you (before), but it seems you want us to make you taste death in all its horror," Zawahiri told "the people of the crusader alliance" led by US President George W Bush [Images] and Blair. "Taste some of what you made us taste," he said.

Zawahiri linked the London bombings to the spurning by European governments of a truce offer by bin Laden.

"Did the lion of Islam, the mujahed Sheikh Osama bin Laden, not offer you a truce so that you may depart from the land of Islam? But you... were led by arrogance to more crime and your (British) Foreign Secretary Jack Straw said that these proposals 'deserve to be met with our contempt,'" Zawahiri said.

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"So taste the result of the insolence of your governments."

In the tape, speaking with Yorkshire accent, one of the London bombers, Mohammad Sidique Khan, said he had forsaken 'everything for what we believe' and went on to accuse Western civilians of being directly responsible for the terror attacks that befall them.

"Your democratically elected governments continuously perpetuate injustice against my people all over the world, and your support makes you directly responsible, just as I am directly responsible for protecting and avenging my Muslim brothers and sisters," Sidique Khan said.