A judge refused to set bail Tuesday for a Pakistani man accused of aiding Al Qaeda (search), saying the suspect was dangerous if he did try to help terrorists sneak into the country after the Sept. 11 attacks.

The ruling by U.S. Magistrate Judge Andrew J. Peck came as prosecutors said they expected to toughen charges against Uzair Paracha (search), 23, who has been held since his March arrest as a material witness in the government's wide terrorism probe.

Paracha's lawyer, Anthony Ricco, revealed Tuesday that his client is accused of meeting with Khalid Shaikh Mohammed (search), who reputedly helped plan the Sept. 11 attacks. The lawyer said he may seek access to Mohammed as he prepares for trial.

Peck rejected a $2.5 million bail package that would have been secured by five properties and pledges from the defendant's aunts and uncles, including two doctors, who live in the New York area.

The complaint alleges that Paracha agreed at a meeting this year in Karachi, Pakistan, to help an Al Qaeda associate get documents to enter the United States and help him obtain legal immigration status. Mohammed is alleged to have been among those at the meeting.

Assistant U.S. Attorney Karl Metzner noted that the case developed after Al Qaeda had promised revenge against the United States for actions it took after Sept. 11.

"It is harder to conceive of a greater threat to our country than one who is willing to exploit access to our country to help Al Qaeda get across our border," Metzner said of Paracha, a permanent U.S. resident and a citizen of Pakistan.

Prosecutors said Paracha, if convicted, could face a minimum of more than 17 years in prison.

Metzner said Tuesday the government expects to bring additional charges. Ricco said he believed new charges would include conspiracy.

Outside court, Ricco suggested that prosecutors were mistaken when they alleged his client and two members of Al Qaeda, including Mohammed, met in Pakistan before Paracha entered the United States last winter.

"Maybe he didn't meet with them as stated in the complaint," Ricco said.