ISLAMABAD, Pakistan — The envelope containing terror mastermind Osama bin Laden's latest message to the world was dropped into a letter box in an upscale neighborhood of the Pakistani capital, the second purported al-Qaida video to come out of this nation in little over a week.
Officials cautioned on Saturday that the tape's release to the Arabic television channel Al-Jazeera's Islamabad office does not prove that bin Laden is in Pakistan.
But its appearance was nonetheless an embarrassment to a nation that bills itself as a key ally in Washington's war on terror and that has spent months focusing its troops on a swath of tribal communities along the Afghan-Pakistan border where the fugitive al-Qaida leader has reputedly been hiding.
Ahmad Muaffaq Zaidan, Al-Jazeera's bureau chief in Pakistan, said the tape was dropped off at the gate of the station's office Friday, just hours before it aired.
"The guard brought it to me along with other mail. It was in an envelope, I opened it and it was a big scoop," Zaidan told The Associated Press. Zaidan immediately sent the tape to Al-Jazeera's headquarters in the Gulf nation of Qatar.
Pakistan has sent tens of thousands of troops to the long and porous border with Afghanistan, concentrating on forbidding North and South Waziristan, where bin Laden and his top deputy, Egyptian surgeon Ayman al-Zawahri, are both believed to be hiding.
Scores of soldiers and civilians have been killed, but the operations so far have not netted any major fugitives, leading to charges that the sweeps are conducted as a political show to curry favor with Washington, which has given Islamabad billions of dollars in aid since President Gen. Pervez Musharraf threw his support behind the anti-terror effort.
Bin Laden appeared far healthier in the video released Friday than many would have suspected, considering speculation that he was already ailing in the winter of 2001 when U.S., Afghan and Pakistani forces began their dragnet. U.S. officials have often described him as holed up in a dank and dreary cave, all but cut off from the outside world.
Pakistani officials were quick to move into damage-control mode on Saturday, saying they had no idea how Al-Jazeera got the tape and insisting its existence did not prove the terror leader was here.
Maj. Gen. Shaukat Sultan, the army spokesman, said the intensity of Pakistan's efforts in North and South Waziristan would make it impossible for bin Laden to hide there.
"Even if the tape was dropped here, that doesn't mean that he is here," Sultan said. "Nobody knows where he is, but he cannot be in Pakistan's tribal areas because of the presence of so many troops."
Added Interior Minister Aftab Khan Sherpao: "I don't think he is in Pakistan."
In Afghanistan, the U.S. military dismissed the videotape as "propaganda," and insisted bin Laden would be caught.
"Although we don't have a timeframe for when bin Laden will be captured, we have full confidence that he will be," U.S. military spokesman Maj. Scott Nelson told reporters.
Asked where bin Laden was hiding, Nelson said the military still suspected he could be somewhere near the Afghan-Pakistani border.
"If we knew exactly where he was, we would be there in a moment and we would have a very happy day and a happy election," Nelson said.
Pakistan has made more than 500 al-Qaida arrests since the Sept. 11 attacks, including a series of arrests this summer that led to a terror warning in the United States.
Observers say the success can be seen as confirmation of Pakistan's cooperation in the war on terror — or as evidence that this is still the nation of choice for many of bin Laden's followers.
The tape was the second released here to a major television network.
ABC News received a tape showing a shrouded man claiming to be an American member of al-Qaida in Pakistan on Oct. 22, then waited several days to air it while it looked into its authenticity.
The man, who spoke in English threatened more attacks and said U.S. streets would "run red with blood."
Intelligence officials, however, have not been able to verify the tape's authenticity, and officials do not have information linking the video to a specific threat, said an intelligence official, speaking on the condition of anonymity.
They also have not been able to positively identify the speaker.
Both the bin Laden video and the one aired by ABC News carried banners attributing them to the Sahab Production Committee, a purported al-Qaida propaganda company.
Talat Massood, a defense analyst and former Pakistani general, said bin Laden probably was in Pakistan, despite the official denials, and that he could be either in the sprawling Pakistani port city of Karachi or well cared for by followers in the tribal region.
"The fact that he has the courage to come out shows that he feel protected in his surroundings," Massood said. His healthy appearance "shows that he is probably living in reasonable comfort and he is being taken care of."
Contributing: Stephen Graham, Sadaqat Jan.