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Although terrorists are kidnapping, killing and even beheading American and other contractors and civilians in Iraq and Saudi Arabia, defense contractors say thousands of workers still want to go overseas.

"There's tons of people who are applying for these jobs … But security has got to be in place, whether that's in Saudi Arabia or Iraq or wherever," said Doug Brooks, president of the International Peace Operations Association.

The beheadings of American Paul M. Johnson Jr. (search) and South Korean worker Kim Sun-il (search) were just the latest terrorist killings of contractors working in those two countries. Others have been kidnapped and still others remain missing with no word of their whereabouts.

The killings of Johnson and Sun-il are just the latest in a series of events that have grabbed headlines and stoked outrage in their home countries.

Four civilian security personnel from Blackwater USA (search) one of the biggest and best-known private security firms working in Iraq — were killed in Fallujah, Iraq, on March 31 after their vehicle was hit by rocket-propelled grenades. Even after their bodies were mutilated, burned, dragged through the streets then hung from a bridge spanning the Euphrates River, employment lines at home grew.

After those murders, "the number of applicants for security companies skyrocketed … these people see it as a real job to do and it needs to be done," Brooks said. "The motivations are mixed — the money's pretty good for the civilian … but $200,000 is pretty useless if you're dead."

Aside from the 20,000 private security personnel in Iraq being used to support the U.S. military, there are thousands of private contractors there helping rebuild oil pipelines, electricity grids and other critical infrastructures.

The exact number of U.S. civilians working in Iraq is unknown because companies decline to release these figures because of security concerns. Experts said that in Saudi Arabia this year, between 30,000 and 35,000 Americans were in the kingdom but that number includes dependants.

Companies that are using contractors in Iraq and Saudi Arabia include Lockheed Martin, DynCorp, International Resources Group, Abt Associates and Stevedoring Services of America.

The U.S. Agency for International Development (USAID) awarded the largest of its postwar Iraq contracts to Bechtel to rebuild power generation facilities, electrical grids, water and sewage systems and airport facilities.

The U.S. Army Corp of Engineers awarded Halliburton subsidiary KBR (search) the main contract to fight oil well fires and reconstruct Iraqi oil fields. Its total contract is worth $10 billion.

These contractors, too, have been victims.

The same group that claims to have kidnapped Johnson says it killed American Kenneth Scroggs, whose body was found June 12 in Riyadh. Scroggs, 58, worked for a British-Saudi company and was shot in the back outside his home in a Riyadh residential neighborhood. He was the third Westerner gunned down in a week and the 29th killed since May 1 in Saudi Arabia.

Another American, Robert Jacobs, was also killed earlier this month. The 63-year-old employee of Vinnell/Arabia, a subsidiary of defense contractor Northrop Grumman Corp., was gunned down in the eastern Riyadh neighborhood of al-Khaleej, which contains several residential compounds for Westerners.

Companies with reconstruction contracts in Iraq are taking various approaches to keeping their workers safe.

"Safety is of paramount importance to Bechtel and as part of our policy, we need to take appropriate steps" to protect their workers, Bechtel spokeswoman Brenda Thompson said of the undisclosed number of Bechtel workers in Iraq. "I can tell you we provide 24-7 security protection for our employees."

Bechtel's American staff in Iraq is chock full and any additional staffing would be done with local Iraqis, Thompson said, adding that Bechtel provides its own security, "in coordination with the military," for its workers.

KBR has stepped up its security precautions and efforts in light of recent events.

"We continue to work closely with coalition authorities regarding the safety and security of all personnel in the region while continuing to deliver the support services required by the soldiers," Halliburton spokesman Wendy Hall told FOXNews.com.

Several workers for Halliburton and KBR — the company formerly known as Kellogg, Brown and Root — have been killed and/or abducted; some are still missing. But still, workers are volunteering to be sent over into the danger zone.

"Halliburton and KBR have more than 100,000 applications on file of people interested in working in the Middle East. In fact, job applications continue to come in at a steady pace," Hall said, adding that "several hundred" personnel are processed each week for deployment to the region.

"I needed a job," Eric Stringer, a KBR employee who recently trained surviving a biological and chemical attack in Houston to be a truck driver in Iraq, told FOX News. "And this is a pretty good opportunity ... to support and take care of my family."

Halliburton maintains that their employees know the danger they face and are prepared.

"The world has been made aware of the threat in Iraq to civilian contractors supporting the troops and Iraqis only recently," Hall said. "Our employees were prepared from Day 1 with the knowledge of the danger and the price that they could pay for their work in Iraq. Not one of our employees leaves the United States for Iraq without thorough and repeated briefings on the dangers in Iraq."

Companies would not elaborate on the exact role of the U.S. military in protecting the contractors.

As for what happens as of June 30, when the U.S.-led coalition hands over sovereignty to the Iraqis, the U.S. military says that while companies provide some if not all of their own security, it has the right to use force if needed.

A spokesman for the Coalition Press Information Center told FOXNews.com that as of June 30, U.S. forces may use force -- including deadly force -- to defend not only themselves but also to protect other friendly forces, Iraqi police and security forces, enemy prisoners of war and detainees, civilians and members of groups such as the Red Cross or U.S.- and U.N.-designated groups from crimes that likely will cause death or other serious harm.

Still, some CEOs say the seemingly increasing number of kidnappings and killings targeting Westerners may affect the way contracting companies do business.

Globaloptions CEO Neil Livingstone told FOX News that he's had some conversations with at least one "major defense contractor" about the environment in Iraq and Saudi Arabia.

"I think a lot of companies probably aren't going to send their people in" and will instead rely on teleconferences and similar methods of conducting business overseas, Livingston said.

"They have great nervousness amongst their employees in that country right now … I can expect some of them probably will leave, others will want more money to stay, others will want more security — there will be a tradeoff."