One of the suicide bombers who struck London's transit system a year ago said in a video broadcast Thursday that the attacks were "only the beginning."
The video, broadcast by Al-Jazeera, showed Shehzad Tanweer delivering the warning shortly before the July 7, 2005, attacks that killed 52 people and the four bombers.
"What you have witnessed now is only the beginning of a string of attacks that will continue and become stronger," Tanweer said in the video, and, in a Yorkshire accent says attacks will continue "until you pull your forces out of Afghanistan and Iraq."
Tanweer, 22, killed six people and himself aboard a London Underground train.
The video includes scenes of an unidentified man circling points on a map of London, as well as statements from Ayman al-Zawahri, al Qaeda's second in command, and American Adam Gadahn, also known as Azzam al-Amriki, who is believed to be running al Qaeda's propaganda operation.
The tape was clearly an attempt to stamp al Qaeda's signature on the attacks, on the eve of their anniversary, reports CBS News' Vicki Barker in London.
Ahmed al-Sheikh, an editor at Al-Jazeera in Doha, Qatar, would not say how or when the Arab broadcaster obtained the video. He said it was a long tape, and the station had shown only a small portion of it.
Andy Hayman, head of Specialist Operations for the Metropolitan Police, said the video would become part of the continuing investigation of the bombings.
Britain's non-Muslims deserve to be attacked, Tanweer says, because they voted for a government which "continues to oppress our mothers, children, brothers and sisters in Palestine, Afghanistan, Iraq and Chechnya."
"There can be no doubt that the release of the video at this time can only cause maximum hurt and distress to the families and friends of those who died on 7/7 and the hundreds of people who were injured in the terrorist attacks," Hayman said.
Prime Minister Tony Blair's office said it had no immediate comment on the video.
In September, Al-Jazeera played a video from another of the four bombers, Mohammad Sidique Khan.
In that video, Khan claimed that the British public were to blame for the terrorist attacks because of their support for Western governments which "continuously perpetuate atrocities" against the Islamic world.
"We are at war and I am a soldier," Khan had said.
Khan's farewell message had been broadcast alongside a video of al Qaeda's No. 2, Ayman al-Zawahri, warning of more attacks. They did not appear together on the recording, but analysts said it provided the strongest link yet between the terrorist network and the four London bombers.
Peter Clarke, who heads the anti-terrorist branch of the Metropolitan Police, said he believed Khan had probably recorded his so-called living will outside of Britain.
"The splicing of the footage with the comments of al-Zawahri and the release through the usual al Qaeda channels suggests it may well have been recorded overseas," Clarke said.
Clarke also confirmed that both Tanweer and Khan had made at least three trips to Pakistan before the bombings, making a final visit in early 2005.
All four of the July 7 bombers were British.
In a recent poll, 16 percent of surveyed British Muslims said they believed the attackers were motivated by a just cause.
The poll, conducted for The Times newspaper and ITV News, found that 13 percent of Muslims felt the bombers should be regarded as martyrs, and 7 percent felt suicide attacks on British civilians were justified in some circumstances. Pollsters surveyed 1,131 adults between June 1-16. The margin of error was plus or minus 3 percentage points.