WASHINGTON — Kansas Sens. Sam Brownback and Pat Roberts have stepped up their battle to block the Obama administration from possibly moving detainees from Guantanamo Bay, Cuba, to Fort Leavenworth, Kan.

The lawmakers have placed legislative holds on several of the White House's appointees for posts in the Departments of Defense and Justice to pressure the administration into clarifying its plans.

The blocked nominees include Rep. John McHugh, R-N.Y., for Army secretary, and others.

"Those are the two primary agencies working on this issue that have not worked with us," Brownback said in a conference call with reporters. "They have not answered questions that are important to us, to the state of Kansas and certainly to the community of Leavenworth."

The White House declined to comment.

President Obama has pledged to close the military detention facility at Guantanamo by January. The military prison at Fort Leavenworth and a civilian prison in Michigan have emerged as likely replacements.

Roberts and Brownback said they want assurances from the administration that it has no plans to use Leavenworth, or at least answers to several questions.

Roberts, who also was on the conference call, said that numerous concerns have come up at town meetings and in discussions with the military command at the fort.

The lawmakers asked for a detailed description of the costs associated with remodeling Leavenworth to accommodate the detainees, covering the medical, security and housing needs.

They also want an analysis on the economic and security impact on state and local government of moving the detainees, and on Kansas City International Airport.

Additionally, they want to know whether the administration has discussed those issues with officials from local schools, hospitals and law enforcement agencies.

Other requests include a briefing from the attorney general, defense secretary or other senior officials; a list of all sites other than Fort Leavenworth under consideration; and a timeline for the final decision on replacing Guantanamo.

Roberts, a former chairman of the Senate Intelligence Committee, said the detainees who would be transferred were "the top 100 worst of the worst."

"This notion of housing terrorists in Fort Leavenworth is, in my opinion, absurd," he said, "and we're doing everything in our power to stop it."