* Guantanamo has $454 million price tag this year
* Many in Congress want Guantanamo to stay open indefinitely
Democratic lawmakers pushing to close the detention center at Guantanamo Bay said on Wednesday its cost has skyrocketed to $2.7 million per inmate this year and argued it is too expensive to keep open while the country is fighting budget deficits.
"This is a massive waste of money," Senator Dianne Feinstein said during a Senate Judiciary subcommittee hearing on the base.
Guantanamo has been dubbed the most expensive prison on Earth, and President Barack Obama in May cited its cost - then calculated at about $900,000 per prisoner - as one of many reasons to close it.
Representative Adam Smith, the top Democrat on the House of Representatives Armed Services Committee, testified during the hearing that the current cost of operating the facility has jumped to $454 million in the fiscal year ended Sept. 30, according to the U.S. Department of Defense, or about $2.7 million for each of the 166 inmates.
Smith said overall, $4.7 billion has been spent running Guantanamo since the facility opened in 2002.
By comparison, super-maximum security prisons in the United States spend about $60,000 to $70,000 at most to house their inmates, analysts say.
Advocates for closure also argue that holding prisoners for years without charge or trial is a stain on the United States. They say Guantanamo is a threat to national security because it is a powerful recruiting tool for militants.
"Our national security and military leaders have concluded that the risk of keeping Guantanamo open far outweighs the risk of closing it because the facility continues to harm our alliances and serve as a recruitment tool for terrorists," Senator Richard Durbin said during the hearing.
Obama came into office in 2009 with the goal of closing down the Guantanamo detention center within a year. Facing stiff opposition in Congress, he has so far failed to do so, even though 86 of the detainees have been deemed to pose no threat to the United States and cleared for release.
A hunger strike that has involved a majority of the inmates - and daily force-feeding of dozens - has fueled the push to shut the detention center.
Durbin, the No. 2 Democrat in the Senate and chairman of the civil and human rights subcommittee that held the hearing, said he and Feinstein met with senior White House officials last week to discuss what they are doing to transfer detainees away from the base.
There is some Republican support, particularly in the Senate, for closing the base. Republican Senators John McCain and Lindsey Graham met with Obama and Vice President Joe Biden last week on a range of national security issues, including Guantanamo, McCain said last week.
But congressional opponents argue that Guantanamo is an essential tool for fighting terrorism, and fault Obama for failing to come up with an alternative.
"Until we are presented with a good, viable strategy for what to do with terrorists who would work night and day to murder innocent Americans, I have a hard time seeing how it is responsible to shut down our detention facilities and send these individuals home," Senator Ted Cruz, the top Republican on the subcommittee, said at the hearing.
The House voted down two amendments to the Defense Appropriations bill on Wednesday that would have forced cutbacks at Guantanamo. One would have prevented further detention of prisoners cleared for release. The second sought to prevent more construction or expansion of detainee facilities.
Republican Representative Bill Young reflected the views of many members of Congress as he opposed the amendments.
"These detainees are bad, bad people. They hate America. They've sworn to kill Americans and in fact they've done so on the battlefield. And that's why when they were captured they were sent to Guantanamo. And that's where they should stay," he said.