They dealt with the Iranian regime first-hand more than three decades ago, when it was founded in an act of war against the U.S., and several survivors of the hostage crisis say the idea of the U.S. negotiating with an unrepentant Tehran makes their blood boil.

For 444 days, the 52 Americans were held prisoner in the U.S. Embassy by the student revolutionaries that would help usher in the hard-line Islamic theocracy that remains in place today. Many of the hostage takers and guards held key roles in the Iranian government then and continue in important positions today.

“I think it’s very naive because the Iranians talk out both sides of their mouth,” said Clair Cortland Barnes, 69, of Leland, N.C, who was a 34-year-old communications officer at the time he was taken hostage. “Their actions betray their conversations. Their conversations say one thing and then they do something else.'

“I think it’s very naive because the Iranians talk out both sides of their mouth.”

- Clair Cortland Barnes, former Iranian hostage

“They have an agenda that is to wipe out Israel and take over America,” he added.

The U.S., along with the other four permanent members of the United Nations Security Council -- Russia, China, United Kingdom and France -- as well as Germany,  are negotiating a deal that could end international sanctions against Iran in return for assurances it will not pursue nuclear weapons. Iran’s history of disguising its pursuit of nuclear weapons, as well as its rhetoric against the U.S., Israel and the West in general, make any deal that comes from the talks suspect, said hostages.

Barnes' sentiment was shared by Israeli Prime Minister Benjamin Netanyahu, who in a speech to the U.S. Congress that he delivered against the wishes of the Obama administration, characterized Iran as the world's leading state sponsor of terrorism and said the regime has "proven time and again that it cannot be trusted."

“Iran’s regime poses a great threat not only to Israel, but also to the peace of the entire world,” railed Netanyahu, who also said he does not "believe that Iran’s radical regime will change for the better after this deal.”

David Roeder, a former U.S. Air Force lieutenant colonel who was attached to the U.S. Embassy when it was overrun by students seeking to overthrow the U.S.-backed Shah of Iran, said the details of the deal that have so far leaked out -- details the U.S. has not confirmed -- make it sound like Iran is being rewarded for bad behavior.

“It doesn’t seem like this is a good deal for the U.S.,” said Roeder, who is now 72 and retired in North Carolina. "It seems as if we are paying a lot of money and not getting much of a return.”

Roeder and other hostages believe they have a right to legal damages from the Iranian assets that are already being released after being frozen for years following the hostage crisis. The former hostages are represented by attorney Thomas Lankford, of Alexandria, Va. 

“Most of them were tortured horribly," Lankford said of the hostages. "Even [though some were] soldiers, no war experience can prepare you for what they endured.”

Lankford said Americans who spent more than a year as captives of a regime that remains in place cannot be expected to trust it in negotiations.

“There’s a large degree of mistrust," Lankford said. "It’s hard for many of them to know what’s in those discussions.”

There is more to earning a place at the negotiating table with the U.S. and world powers than simply paying the hostages a settlement, said Donald Cooke, who was the embassy's vice consul when he was taken hostage. Iran must own up to the criminal violence in which the current regime was forged, he said.

“If they want to negotiate, they have to deal with the issue of the hostage taking, which the current government is still responsible for," said Cooke, 61, of Maryland. “The Iranian government has to take responsibility or you can't take them seriously in any negotiations.”

Like several of the former hostages, Cooke said he watched the Israeli prime minister's speech with keen interest.

“Benjamin Netanyahu had a good point when he spoke to Congress," Cooke said. "Any negotiation should not be about technical issues. The negotiation should be about changing behavior, and it is not.”

Former U.S. Marine Rodney “Rocky” Sickmann, 57, of St. Louis, was a 22-year-old guarding the embassy in Tehran when his life was changed forever.

"I truly believe that the war on terrorism started on Nov. 4, 1979, when I was a young Marine standing guard at the embassy," he said. "I was only 30 yards away from that fence when they came over it. They used Iranian women as shields when they broke in because they knew we’d stand down.”

Like other survivors, he believes Iran has never answered for its actions.

“They have never been held accountable for what they’ve done to us," Sickmann told FoxNews.com, recounting how he was tied to a chair for days while held by the Iranians. "How do you trust a government that publicly says Israel needs to be eliminated? Anyone should understand why Israel needs to be concerned."

Not all of the surviving hostages believe participating in talks with Iran is a bad idea. Kathryn Koob, who was 41 at the time of the crisis, and was in Tehran serving as director of the Iran-America society, a nonprofit organization established by the U.S. government to strengthen educational and community ties between the two countries, said talking is better that not talking.

“I am glad to see that that is happening,” said Koob, who lives in Waterloo, Iowa, and was one of just two females held hostage by the Iranians. “I think it’s terribly important to engage with all countries in the world, including Iran.

The U.S. has not had formal diplomatic relations with Iran since the crisis, but Koob said the talks, along with a thaw in U.S. relations with Cuba, are a heartening sign.

“Diplomacy does not mean agreement,” Koob said. “I think discussion is better than doing nothing. You can’t accomplish anything by not speaking to a country and pretending they’re not there.”