A Manhattan coffee cart operator currently under 24-hour surveillance by federal agents told ABC News he is not affiliated with al Qaeda and that about one dozen black backpacks and a small scale found in his apartment, identified as suspicious in court documents, are purely coincidental. Facts in the case that have led officials to keep him under constant watch, he said, have been misconstrued.

First, there's the fact that Khan let Najibullah Zazi, the 24-year-old at the center of an alleged bomb terror plot, stay at his Queens, NY apartment Sept. 10. He was also in Pakistan at the same time as Zazi last year. And when FBI agents raided his apartment two weeks ago, they say they found the backpacks that might be used to carry bombs and the scale that could be used to measure ingredients for a bomb.

"It was just by chance that [Zazi] came to our house" that night, Khan told ABC News.

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Khan, who came to the U.S. in 1999 as a high school student, said he and his five roommates have no idea where the scale came from and had not seen it before.

The backpacks, Khan said, belong to his uncle, Faiz Mohammed, who said he got them for free from an acquaintance who acquired them through a wholesale business and that he planned to bring them to family members in Pakistan.