U.S. President Barack Obama is defending his controversial plan to close the military prison at Guantanamo Bay Cuba, in the face of growing opposition in the U.S. Congress, and within his own party.

Obama said Thursday he was determined to shut down the facility and clean up the "mess" left over by the previous Bush administration.

He also defended his plan to transfer some terror suspects held there to top-security prisons in the United States, declaring that this would in no way endanger American security.

But many in the U.S. Senate, led by majority Democrats, are against the idea, and yesterday denied him the funding to close down Guantanamo.

Lawmakers said they would block the funds until Obama gave a more detailed accounting of what would happen to the detainees.

There are 240 detainees at Guantanamo now, including Canadian Omar Khadr. He is the last westerner being held there.

Obama said 50 terror suspects had been cleared to be transferred to other countries, although he did not identify those. It's unknown if Khadr is on that short list.

Speaking at the U.S. National Archives, Obama said it's time to deal head on with this issue.

"We will be ill-served by the fear-mongering that emerges whenever we discuss this issue," he declared.

"I can tell you that the wrong answer is to pretend like this problem will go away if we maintain an unsustainable status quo," Obama said. "As president, I refuse to allow this problem to fester. Our security interests won't permit it. Our courts won't allow it. And neither should our conscience."

Obama said the military prison "set back the moral authority that is America's strongest currency in the world."

That sentiment was echoed by Paul Champ, a human rights lawyer with Amnesty International.

Champ said on Â鶹ӰÊÓnet that Guantanamo had "become a symbol of American injustice and human rights abuses."

He said detainees are being categorized, according to the evidence against them.

The most serious group, Champ said, were those "people they want to charge, and they have enough evidence to charge. The question where do you charge them, and what rules apply."

The next group Champ explained were detainees the U.S. has "concerns and suspicions about, but they don't want to release these people because they are fearful they may engage in terrorist activities."

After that, Champ said, were "people that they don't have anything against, but can't release back to their countries of citizenship because they are now at risk of being tortured."

Just across town from where Obama spoke, former U.S. Vice President Dick Cheney strongly defended the Bush-era terror policies, and said under the same circumstances he would make the same decisions "without hesitation."

In a speech Cheney said "enhanced interrogation techniques" carried out at Guantanamo saved thousands of lives.

Cheney argued the Bush administration "didn't invent" the authority exercised in the war against al Qaeda. He said it was clearly granted by the U.S. Constitution and legislation passed by Congress after the September 11 attacks.

Cheney said he thought Obama policies have weakened, not strengthened, America's ability to fight terror.

With files from Associated Press