Washington (CNN) -- Attorney General Eric Holder said Wednesday the Justice Department is "close to a decision" on whether alleged 9/11 mastermind Khalid Sheikh Mohammed should be tried in a military court or a civilian one either in New York City or elsewhere in the United States.
"The process is an ongoing one," Holder told reporters. "We are working to make a determination about the placement of that trial, and I would hope that whatever the decision is, it would be one that would be judged on merits."
Whatever "is best for the case and for justice in that case will be the thing that will guide the decision," he asserted.
The question of how and where to prosecute Mohammed and other alleged 9/11 conspirators has been deliberated within the Obama Justice Department since last year. Holder told members of the Senate Judiciary back in April that he expected to be "in a position to make (a) determination ... in a number of weeks."
Last November, Holder announced his intention to try Mohammed in New York. A firestorm of opposition, however, erupted from both Republican leaders and New York officials. Mayor Michael Bloomberg eventually withdrew his support for holding Mohammed's trial in the city after businesses and neighborhood groups in the Financial District asked him to reconsider.
Rep. Peter King of New York, the top Republican on the House Committee on Homeland Security, issued a statement immediately after Holder's remarks Wednesday, urging the attorney general "not to hold any 9/11 trials in New York or anywhere in the United States."
"These 9/11 terrorists should be tried before a military commission at Guantanamo," he said, referencing the controversial military detention facility in the U.S. base at Guantanamo Bay, Cuba.
On Tuesday, the international advocacy group Human Rights Watch started airing a 30-second commercial in 11,800 New York City yellow cabs asking the Justice Department to try Mohammed and other defendants in a New York City federal court, rather than before a military tribunal.
The Justice Department has issued no response to the ad campaign.
The civilian trial for Guantanamo detainee Ahmed Ghailani is believed to be heading toward a conclusion in a Manhattan courtroom this week.
Ghailani, according to prosecutors, helped build a truck bomb used in a 1998 terror attack on the U.S. Embassy in Tanzania, one of two embassy bombings in Africa that killed 224 people, including a dozen Americans.
Last month, Holder brushed aside questions about problems prosecutors have faced calling a key witness in Ghailani's trial, noting that there have "been over 300 successful prosecutions of people who were involved in terrorist activities in Article III (civilian) courts. They have been successfully prosecuted."
CNN's Carol Cratty, Jim Barnett, and Alan Silverleib contributed to this report