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Republican lawmakers are calling on the Obama administration to produce a plan for closing the Guantanamo Bay detention center as Attorney General Eric Holder struggles to find new homes in Europe for the prison's detainees.

Guantanamo currently houses 240 detainees, about 60 identified by the Bush administration as being unable to be returned to their countries of origin because of fears they will be tortured or executed there.

Holder announced Wednesday that 30 detainees have been cleared for release or transfer, up from an earlier announcement of 17. He did not indicate whether they will be set free or put in prison when they find a new home.

"We have about 30 or so where we've made the determination that they can be released. So we will, I think, relatively soon, be reaching out to specific countries with specific detainees and ask whether or not there might be a basis for the moving of those people from Guantanamo to those countries," Holder said while in Germany.

The attorney general has been traveling in Europe this week to press countries to accept the "shared responsibility" of closing the naval prison. So far, France has formally agreed to take in a single detainee as a symbolic gesture; many other countries have signaled their unwillingness to assist.

Several countries in Europe are reluctant to take the prisoners, partly because of the security risk and partly because of the cost.

"If the detainees are no longer dangerous, why don't they stay in the U.S.?" Austrian Interior Minister Maria Fekter asked in March. "For Austria, I cannot accept Guantanamo inmates."

Republican lawmakers on Wednesday blasted President Obama for what Sen. Kit Bond calls a "ready, fire, aim" policy that demands the facility be closed by next year without a plan for placing the remaining prisoners -- or even determining whether they will be freed or put through a criminal trial.

"Like me, Missourians -- all Americans -- are still waiting for Obama to make the case that his decision to release the detainees at Guantanamo is in our country's national security interest; the president has failed to make the case that the release of these terrorist-trained detainees will make us safer; the president has failed to make the case that the release of these terrorist-trained detainees won't pose a threat to American citizens," Bond said in a speech on the Senate floor.

"To date, the administration has not provided the American people with any specifics about what will happen with these inmates" when the naval prison is closed in January, Senate Majority Leader Mitch McConnell wrote Wednesday in an op-ed carried by Reuters.

A Justice Department official said the Guantanamo Review Task Force charged with closing the detainees has made significant progress in the past three months and will "continue to provide the public with additional updates on its efforts."

"The Justice Department is committed to ensuring that each of these individuals are addressed through responsible policies that are consistent with interests of justice and the national security and foreign policy objectives of the United States," a spokesman said.

Holder said any decisions about where the detainees will be housed are weeks away.

"We must devise a plan that abides by American and international law while ensuring the safety of the American people," he said in Berlin. "For some detainees, the decision will be fairly easy. Some, we will conclude, no longer pose a threat to the United States and can be released or transferred into the custody of other countries."

Convincing Europe to accept the prisoners is a tough sell, said Benjamin Wittes, a senior fellow for governance studies at the Brookings Institution.

"The American toolbox in persuading other countries to take Guantanamo detainees is a very weak palette of tools," he said.

Some countries have been amenable. Ireland has repeatedly signaled that it will take in detainees, and Portugal, Switzerland and Lithuania are also expected to offer help.

But that offer that can come at a cost. Some released detainees, such as Binyam Mohamed, who was released in Britain in February after spending five years in Guantanamo, have ended up on government assistance in Europe. And the transfer of the detainees itself can be quite expensive. Australia spent hundreds of thousands of dollars reclaiming two of its citizens from Guantanamo.

Asked how a detainee released in another country would make a living, a Justice Department spokesman would only say, "Any security or assimilation measures would be up to the government accepting such detainees."

The Department of Justice declined to answer questions from FOX News asking whether the U. S. would offer incentives to European countries to take in detainees, including covering of costs to fly them home or to house them on arrival.

The cost of releasing the prisoners could be great. Amnesty International says the United States "has an obligation under international law to provide prompt and adequate reparation" to any detainees held illegally or ill-treated during their incarceration.

The administration already has an $80 million bankroll to help close Guantanamo, but the money alone may not be enough to ensure a smooth transition for the detainees before the president's January deadline.

"Translating 'Close Guantanamo' into an action plan that involves resettling people is very difficult," said Wittes. "I don't envy the attorney general his task right now."

Director of National Intelligence Dennis Blair has indicated that detainees released in the U.S. would likely receive government assistance to help them return to society -- one they've never been a part of.

"If we are to release them in the United States, we need some sort of assistance for them to start a new life," Blair said last month. "You can't just put them on the street."

Rep. Lamar Smith, R-Texas, ranking Republican of the House Judiciary Committee, said it will be the full responsibility of the Obama administration if any additional crimes or terrorist attacks are committed once the detainees are released to their own devices.

Smith added that he is disappointed that the attorney general hasn't briefed Congress on the administration's plan to close Guantanamo Bay.

"Releasing terrorists endangers American lives both here and abroad," he said in a statement. "The American people have a right to know how these decisions are being made; yet this administration is sharing more information with foreign countries at overseas press conferences than with U.S. members of Congress elected to represent the American people."

FOX News' Mike Levine contributed to this report.