New York (CNN) -- A key witness at the trial of the first Guantanamo detainee to be tried in the United States cannot testify because of concerns over torture, a judge ruled Wednesday.
The man on trial, Ahmed Ghailani, told the Central Intelligence Agency about the witness while agents were interrogating him, and the government has conceded that everything Ghailani said in CIA custody can be considered to have been coerced.
"The government has elected not to litigate the details of Ghailani's treatment while in CIA custody," Judge Lewis Kaplan noted in his ruling Wednesday.
"In these circumstances, the Constitution does not permit [Hussain] Abebe to testify in this criminal trial," the judge added. He left a potential opening for the government if it can show there was little connection between the identification of Abebe as a possible witness and the CIA's treatment of Ghailani.
The ruling is a victory for Ghailani's defense attorneys, who had asked that Abebe not be allowed to testify.
Ghailani is accused of involvement in the 1998 bombings of United States embassies in Kenya and Tanzania. The attacks killed 224 people, including 12 Americans.
He has pleaded not guilty.
Ghailani's attorneys had previously argued that his entire indictment should be thrown out on the grounds that he was tortured by the CIA, violating his rights under the due process clause of the Constitution.
"If, as Ghailani claims, he was tortured in violation of the Due Process Clause, he may have remedies. For the reasons set forth above, however, those remedies do not include dismissal of the indictment," Kaplan wrote in his opinion denying that motion.
Opening arguments in the trial were expected to begin Wednesday, but the prosecution asked for 48 hours to decide whether to appeal the judge's ruling.
Court is now delayed until October 12, when potential jurors are scheduled to come back to complete the jury selection.
Wednesday's ruling underscores the legal difficulties inherent in the Obama administration's plan to try former Guantanamo Bay detainees in civilian courts on U.S. soil.
But Attorney General Eric Holder said the trial would go ahead.
"I think it's too early to say at this point the Ghailani matter is not going to be successful," he said after the ruling. "We have to deal with this one ruling, and we will.... We intend to proceed with this trial."
The Tanzanian national was held in the camp at the U.S. base in Cuba from September 2006 until June of last year.
Ghailani's arrival in New York came amid tension between Congress and President Barack Obama over the planned closing of Guantanamo.
The transfer "sets a dangerous precedent for the more than 200 suspected terrorists currently held at Guantanamo Bay," said Judiciary Committee Ranking Member Lamar Smith, R-Texas, in a written statement.
By bringing Ghailani to the United States, the Obama administration "is granting a terrorist and murderer additional constitutional rights," he said. "Even if convicted, Ghailani could be released in the U.S. after serving his sentence."
The 1998 embassy attacks are among several crimes for which Ghailani has been indicted in New York. He was captured in Pakistan in 2004 and taken two years later to Guantanamo.
Ghailani faces 286 counts in the indictment against him.
His alleged crimes include conspiring with al Qaeda leader Osama bin Laden and other members of the terrorist group to kill Americans anywhere in the world.
He also faces separate charges of murder for each of the 224 people killed, and other offenses related to the bombings.
CNN's Mark J. Norman, Sheila Steffen, Deborah Feyerick, Terry Frieden and Ashley Hayes contributed to this report.