After that, he said, the prosecution will bring charges against some senior Qaeda figures whom he would not name.

Pakistan has been a sanctuary for some Qaeda figures since soon after the American-led invasion of Afghanistan.

Increasingly, however, the authorities suspect that the Qaeda figures believed to have been involved in the surveillance were active members of the terrorist network.

Mr. Siddique said that during the trip he had met with two senior Qaeda figures, the official said.

Officials are also divided and somewhat puzzled about Iran's role in pursuing Qaeda figures.

The American officials said the new evidence had been obtained only after the capture of the Qaeda figure.

The suspect, Abu Zubaydah, is the most senior Qaeda figure captured since Sept. 11.

Besides Mr. bin al-Shibh, other senior Qaeda figures are believed to have been in the city recently.

American officials say that several Qaeda figures were among those killed, but have not determined who they were.

But other administration officials suggested that most or all of them were not major Qaeda figures.