Cairo ? Two of the four suicide bombers who attacked London a year ago spent time at an al-Qaida camp to prepare themselves for a suicide mission, the deputy leader of the terror network claimed in a video Friday.

British authorities previously said they knew Shehzad Tanweer and Mohammad Sidique Khan had visited Pakistan, but the comment from al-Qaida No. 2 man Ayman al-Zawahri was the first to claim that they had been at an al-Qaida base.

“Both of them were seeking martyrdom and wished that they could carry out a martyrdom operation,” al-Zawahri said, using the Islamic euphemism for a suicide attack.

It was not possible to independently verify his claim, which was part of a video posted on the Internet on the first anniversary of the July 7, 2005, suicide bombings that killed 52 commuters on three subway trains and a bus in London.

The video also contained a harangue by an English-speaking al-Qaida member against British and U.S. involvement in the Middle East and Asia, saying no Muslim should “shed tears” for Westerners killed by al-Qaida attacks.